Choke left out -- that's odd (7)
I believe the answer is:
strange
'odd' is the definition.
(I've seen this before)
'choke left out' is the wordplay.
'choke' becomes 'strangle' (I've seen this before).
'left' becomes 'l' (common abbreviation).
'out' is a deletion indicator.
'strangle' with 'l' removed is 'STRANGE'.
'that's' is the link.
(Other definitions for strange that I've seen before include "Odd, peculiar" , "Eccentric" , "Out of the ordinary" , "Singular" , "Surreal" .)