Left a little chap out, having slipped (4)
I believe the answer is:
slid
'slipped' is the definition.
('slide' can be a synonym of 'slip')
'left a little chap out' is the wordplay.
'left' becomes 'l' (common abbreviation).
'a little chap' becomes 'sid' (man's name. I am not sure about the 'little' bit.).
'out' means one lot of letters goes inside another.
'l' placed into 'sid' is 'SLID'.
'having' acts as a link.
Can you help me to learn more?
(Other definitions for slid that I've seen before include "Slipped" , "Moved (eg, on ice)" , "Moved smoothly along a surface" , "Skidded, slewed" .)