noun, na-adjective
extremely cowardly and mean; utterly unsportsmanlike
A strong yojijukugo condemnation of someone's character or behavior as both cowardly and underhanded. Often used in heated accusations.
そんなやり方は卑怯千万だ。
That way of doing things is utterly cowardly and mean.
彼の卑怯千万な態度に皆が怒った。
Everyone got angry at his extremely sneaky attitude.
A yojijukugo combining 卑怯 (cowardly, unfair) with the emphatic suffix 千万 (extremely). The exact origin is uncertain, but it follows a common pattern of intensifying a two-character word with 千万.