Teetotaller secretes wee dram (3)
I believe the answer is:
tot
'wee dram' is the definition.
(I've seen this in another clue)
'teetotaller secretes' is the wordplay.
'secretes' says the answer is hidden in the clue (I've seen 'secreted' mean this).
'TOT' can be found hidden inside 'teetotaller'.
(Other definitions for tot that I've seen before include "Rum measure" , "Add up for baby" , "two fingers, perhaps" , "Add; small child" , "Nip" .)