Dad has half of it ready (3)
I believe the answer is:
pat
'ready' is the definition.
(I've seen this in another clue)
'dad has half of it' is the wordplay.
'dad' becomes 'pa' (both can mean one's father).
'has' says to put letters next to each other.
'half of' suggests halving the letters.
'it' with half the letters taken is 't'.
'pa'+'t'='PAT'
(Other definitions for pat that I've seen before include "Tap lightly" , "Conveniently; light touch" , "Touch; name" , "Touch lightly - bit of butter?" , "Slick; dab" .)