Boffin no longer frisky? (6)

I believe the answer is:

expert

'boffin' is the definition.

'no longer frisky?' is the wordplay.
'no longer' becomes 'ex'.
'frisky?' becomes 'pert' (both can mean lively).
'ex'+'pert'='EXPERT'

(Other definitions for expert that I've seen before include "Specialist, pundit" , "Skilled workman or specialist" , "One has specialist knowledge or ability" , "Clever" , "Masterly" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.