Coffee mug daughter upset (5)
I believe the answer is:
decaf
'coffee' is the definition.
(type of coffee)
'mug daughter upset' is the wordplay.
'mug' becomes 'face' (I've seen this in another clue).
'daughter' becomes 'd' (genealogical abbreviation).
'upset' says the letters should be written backwards.
'face'+'d'='faced'
'faced' back-to-front is 'DECAF'.
(Other definitions for decaf that I've seen before include "Non-alcoholic drink" , "Coffee without the kick?" , "Type of coffee" , "Style of coffee" , "Cup substitute missing kick" .)