New recruit drops from sky to penetrate sporting target (7)
I believe the answer is:
trainee
'new recruit' is the definition.
(I've seen this before)
'drops from sky to penetrate sporting target' is the wordplay.
'drops from sky' becomes 'rain' (drops of water from the sky).
'to penetrate' means one lot of letters goes inside another.
'sporting target' becomes 'tee' (golfers hit the ball off a tee).
'rain' going within 'tee' is 'TRAINEE'.
(Other definitions for trainee that I've seen before include "Person being instructed in work" , "New recruit" , "encountered bad weather in driving area" , "As pupil" , "21 [TYRO]" .)