Want to bump off daughter ... what are you on? (5)
I believe the answer is:
earth
'are you on?' is the definition.
I can't judge whether this defines the answer.
'want to bump off daughter' is the wordplay.
'want' becomes 'dearth' (both can mean a lack or scarcity).
'to bump off' suggests deleting specific letters.
'daughter' becomes 'd' (genealogical abbreviation).
'dearth' with 'd' taken out is 'EARTH'.
'what' acts as a link.
Can you help me to learn more?
(Other definitions for earth that I've seen before include "Soil; electrical connection" , "Fox's or badger's lair" , "Terra firma" , "Connection between an electrical device and conductor" , "Heart (anag)" .)