Feel a bit unbalanced in what's an irritable spot

I believe the answer is:

fleabite

I'm a little stuck... Click here to teach me more about this clue!

(Other definitions for fleabite that I've seen before include "Very minor inconvenience" , "Irritating thing" , "Minor irritation" , "Belie fat as trivial inconvenience" , "mild irritation" .)

I've seen this clue in the Irish Times.

Want a hint initially instead of a full solution? Install my app