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 tell whether this definition defines the answer.
'want to bump off daughter' is the wordplay.
'want' becomes 'dearth' (both can mean a lack or scarcity).
'to bump off' indicates named letters should be taken away.
'daughter' becomes 'd' (genealogical abbreviation).
'dearth' with 'd' taken out is 'EARTH'.
'what' is the 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)" .)