Nimble as very slightly drunken newt (4)
I believe the answer is:
deft
'nimble' is the definition.
(thesaurus)
'drunken newt' is the wordplay.
'drunken' becomes 'd' (this might be a standard abbreviation which I don't know about).
'newt' becomes 'eft' (eft is a kind of newt).
'd'+'eft'='DEFT'
'as very slightly' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for deft that I've seen before include "Dextrous" , "Adept" , "Adroit, skilful" , "Quick and skilful in movement" , "Handling things skilfully or neatly" .)