Bimbo’s bottom pinched by a little creep (4)
I believe the answer is:
toad
'creep' is the definition.
(I've seen this in another clue)
'bimbo's bottom pinched by a little' is the wordplay.
'bottom' indicates one should take the final letters.
'pinched by' means one lot of letters goes inside another (inserted letters get pinched or taken).
'a little' becomes 'tad' (both can mean a small amount).
The final letter of 'bimbo' is 'o'.
'o' inserted into 'tad' is 'TOAD'.
(Other definitions for toad that I've seen before include "Loathsome creature" , "Wind in Willows hall-owner" , "Dangerous driver" , "Amphibian with warts" , "Small amphibian" .)