Company left pass
I believe the answer is:
col
'pass' is the definition.
(col is a term for a mountain pass)
'company left' is the wordplay.
'company' becomes 'co' (abbreviation).
'left' becomes 'L' (common abbreviation).
'co'+'l'='COL'
(Other definitions for col that I've seen before include "Pass between mountain ridges" , "A depression in mountain range" , "dip?" , "Low area between peaks" , "Depression among ecologists" .)