Trap quickly springs back — end of mouse (5)
I believe the answer is:
noose
'trap' is the definition.
(I know that noose is a type of trap)
'quickly springs back end of mouse' is the wordplay.
'quickly' becomes 'soon' (I've seen this in other clues).
'springs back' is a reversal indicator (I've seen 'springing back' mean this).
'end of' indicates one should take the final letters.
The final letter of 'mouse' is 'e'.
'soon' back-to-front is 'noos'.
'noos'+'e'='NOOSE'
(Other definitions for noose that I've seen before include "Hangman's halter" , "Hangman's knot" , "Loop with running knot" , "Hanging loop in rope" , "Catcher" .)