Gainly means: Written ganelie Sc. [ge-nli, gea'nli, gia'nli.] 1. adv. Conveniently or handily placed or situated ; easy of access. Also used as adj.. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. 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.