Bit from Fleet Admiral (3)
I believe the answer is:
tad
'bit' is the definition.
(both can mean a small amount)
'from fleet admiral' is the wordplay.
'from' indicates a hidden word.
'TAD' is hidden in the letters of 'fleet admiral'.
(Other definitions for tad that I've seen before include "Small bit" , "(A) bit, touch" , "little boy" , "Small amount or degree" , "A small amount (colloq.)" .)