The odd street light? (5)
I believe the answer is:
stray
'the odd' is the definition.
(thesaurus)
'street light?' is the wordplay.
'street' becomes 'st' (abbreviation).
'light?' becomes 'ray' (ray is a kind of light).
'st'+'ray'='STRAY'
(Other definitions for stray that I've seen before include "Deviate" , "Go off course" , "digress" , "Appearing occasionally" , "Drift - isolated" .)