IPA: /ˈnɛt.əl.ɪər/
KK: /ˈnɛtliər/
A person or thing that nettles, which means to irritate or annoy.
The nettlier in the group always found a way to provoke others.
The word 'nettlier' comes from 'nettle' (from Old English 'netele', meaning a stinging plant) and the suffix '-ier' (meaning one who). A 'nettlier' refers to one who deals with or is associated with nettles.
Think of someone who is associated with a stinging plant ('nettle') — the '-ier' indicates a person involved with it.