1
socio;compinche;cómplice
1
partner;pal;accomplice
こいつ、さっきまで俺の相棒だったのに、もう寝返りやがった。
This rat, up until just now he was my partner and now he's gone and turned on me.
Other forms
合棒 【あいぼう】 (search-only kanji form)