Danger through, I left (5)
I believe the answer is:
peril
'danger' is the definition.
(synonyms)
'through i left' is the wordplay.
'through' becomes 'per' (I've seen this before).
'left' becomes 'l' (common abbreviation).
'per'+'i'+'l'='PERIL'
(Other definitions for peril that I've seen before include "Great danger" , "Exposure to harm" , "Danger, hazard" , "risk" , "Source of danger" .)