A mug of schnapps, apparently (3)
I believe the answer is:
sap
'a mug' is the definition.
(thesaurus)
'of schnapps apparently' is the wordplay.
'of' indicates the answer is hidden within the clue.
'SAP' can be found hidden inside 'schnapps apparently'.
(Other definitions for sap that I've seen before include "The juice in trees" , "sucker" , "Imbecile" , "It's plant juice, idiot" , "Tree's blood" .)