Lends a hand to headless busts? (4)
I believe the answer is:
aids
'lends a hand' is the definition.
I can't judge whether this defines the answer.
'headless busts?' is the wordplay.
'headless' means to remove the first letter.
'busts?' becomes 'raids' ('raid' can be a synonym of 'bust').
'raids' with its first letter removed is 'AIDS'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for aids that I've seen before include "Assists" , "Helps with a dread disease" , "Condition following infection with HIV virus" , "Said to be a modern plague" , "Said to be an international disease" .)