Escape, having left before noon (3)
I believe the answer is:
lam
'escape' is the definition.
(lam is a kind of escape)
'left before noon' is the wordplay.
'left' becomes 'l' (common abbreviation).
'before noon' becomes 'am'.
'l'+'am'='LAM'
'having' acts as a link.
(Other definitions for lam that I've seen before include "Batter" , "On this, you're fleeing, from the police" , "Escape, get away" , "hurried flight" , "Hit hard, strike" .)