Introduce first of paratroopers, then withdraw (7)
I believe the answer is:
precede
'introduce' is the definition.
(thesaurus)
'first of paratroopers then withdraw' is the wordplay.
'first of' says to take the initial letters.
'then' is a charade indicator (letters next to each other).
'withdraw' becomes 'recede' (receding is a kind of withdrawing).
The initial letter of 'paratroopers' is 'p'.
'p'+'recede'='PRECEDE'
(Other definitions for precede that I've seen before include "Go before (someone)" , "Go ahead of" , "Come before (something)" , "go before the others" , "Go in front" .)