Chainsaw consultant means: A consultant whose job is to assist in downsizing a workplace.. It is informal slang, fine in casual speech but not suited to formal contexts. It is generally derogatory or offensive; worth a quiet word about how it lands on the person being described. As a place or proper-name reference it is purely descriptive. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.