'Knackered' is British and Irish English for 'exhausted'. 'I'm knackered' just means 'I'm shattered, I'm worn out'. It comes from the older noun 'knacker' (someone who slaughtered worn-out horses), so the metaphor is 'worn out like an old horse'. If your teen uses it, they are using everyday British English. The word is mild and acceptable in most British conversations, though older speakers may find it slightly coarse.
knackered
British: completely exhausted.
Etymology timeline
Born ~2002 · 1 year of recorded useSeen in the wild
Feeling knackered this evening and fancied an early night, but then I remembered the PSG Bayern game was on, so gutted. Now seen it’s the snooze fest and PSG Bayern is tomorrow 😃 What a result. Early night it is.
Looking at it again, the second time looks deliberate, but with an odd lateral movement attached to it. The first time it's like he thinks to catch his flapping tie, then changes his mind halfway through. He looks kna…
It's coming up on 8pm here and I'm sunkissed but absolutely knackered. I don't think I can make the Arsenal game
It’s a double trap. If they hire him and it goes tits up, they’re knackered again. If they don’t and the new guy goes tits up, it’s the same. DOUBLE ADMIRAL ACKBAR
He would wish his audiences "All the very best" along with, "I'm knackered now, aren't you?
Definitions
British: completely exhausted. Can also describe something broken beyond repair. "Knackered from the commute," "car is knackered," "back is knackered." Multipurpose but always negative.
“He would wish his audiences "All the very best" along with, "I'm knackered now, aren't you?”
“Feeling knackered this evening and fancied an early night, but then I remembered the PSG Bayern game was on, so gutted. Now seen it’s the snooze fest and PSG Bayern is tomorrow 😃 What a result. Early night it is.”
“Looking at it again, the second time looks deliberate, but with an odd lateral movement attached to it. The first time it's like he thinks to catch his flapping tie, then changes his mind halfway through. He looks knackered though.”
"I'm knackered — seven hours on my feet."
'Knackered' is British and Irish English for 'exhausted'. 'I'm knackered' just means 'I'm shattered, I'm worn out'. It comes from the older noun 'knacker' (someone who slaughtered worn-out horses), so the metaphor is 'worn out like an old horse'. If your teen uses it, they are using everyday British English. The word is mild and acceptable in most British conversations, though older speakers may find it slightly coarse.
'Knackered' is informal British and Irish English meaning 'exhausted, completely worn out'. Origin: the older noun 'knacker' (someone who slaughtered worn-out horses), giving the metaphor 'worn out like an old horse'. Register: informal British English; acceptable in most casual conversation but mildly coarse in some older or formal settings. In formal English use 'exhausted' or 'fatigued'. A common learner mistake is to use it in American English, where it is largely unknown and may be misheard.
“Feeling knackered this evening and fancied an early night, but then I remembered the PSG Bayern game was on, so gutted. Now seen it’s the snooze fest and PSG Bayern is tomorrow 😃 What a result. Early night it is.”
— Bluesky· May 2026“Looking at it again, the second time looks deliberate, but with an odd lateral movement attached to it. The first time it's like he thinks to catch his flapping tie, then changes his mind halfway through. He looks knackered though.”
— Bluesky· May 2026“It's coming up on 8pm here and I'm sunkissed but absolutely knackered. I don't think I can make the Arsenal game”
— Bluesky· May 2026“It’s a double trap. If they hire him and it goes tits up, they’re knackered again. If they don’t and the new guy goes tits up, it’s the same. DOUBLE ADMIRAL ACKBAR”
— Bluesky· May 2026“He would wish his audiences "All the very best" along with, "I'm knackered now, aren't you?”
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Why is this section here?
Slang is read by different audiences for very different reasons. The For parents view re-explains the term in plain, non-judgemental language so a caregiver can understand what their child means without needing the surrounding subculture. The For English learners view focuses on register (when it's safe to use), formal alternatives, and common mistakes — what a textbook won't teach you.
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🇬🇧About British & Irish slang slang
UK and Irish slang — Cockney, Scouse, Geordie, Yorkshire, Glaswegian, Brummie, Welsh, West Country, plus Irish English. Centuries of regional dialects feeding into modern British and Irish street talk.
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- nadgered76%
(UK, slang) Tired or exhausted; knackered.
- peak knackered75%
The point at which exhaustion has reached its absolute ceiling — you cannot get more tired, your body has submitted a formal resignation, and your brain is basically screensaver mode. Peak knackered is used to signal you've hit the terminal level of depletion, often with a kind of bewildered disbelief that you are still functional at all. British slang speakers use 'peak' both as an intensifier and as a superlative marker, making this compound immediately readable as maximum tiredness without ambiguity.
- shattered75%
(British, colloquial) Extremely tired or exhausted.
- mega knackered74%
A step beyond ordinarily wrecked — mega knackered is what happens when regular exhaustion gets stacked on top of more exhaustion, until you've reached a level of tiredness that feels almost theatrical. You're not just tired, you're spectacularly, cosmically, almost impressively destroyed. The word mega adds an element of dark comedy, implying the speaker has somehow lapped the normal fatigue dial and ended up somewhere absurd. Used with a mixture of complaint and reluctant pride that you've achieved peak depletion.