Put a match to high explosive -quick to move! (5)
I believe the answer is:
lithe
'quick to move' is the definition.
(I've seen this before)
'put a match to high explosive' is the wordplay.
'put a match to' becomes 'lit' (I've seen this in another clue).
'high explosive' becomes 'he'.
'lit'+'he'='LITHE'
(Other definitions for lithe that I've seen before include "Physically supple, agile" , "Elastic" , "Slim and supple" , "grace" , "Slim, graceful" .)