also: むしがよい
expression, i-adjective (yoi/ii class)
selfish; presumptuous; asking too much
Describes a person who is self-centered or makes unreasonable demands, often without considering others. The phrase literally means 'the bug is good,' referring to an inner selfish nature.
See also: 虫のいい
彼は虫がいいから、いつも自分のことしか考えない。
He's selfish, so he always thinks only about himself.
そんな虫がいい話は通らないよ。
Such a presumptuous proposal won't be accepted.
Synonymous expression; 虫のいい is a variant with the same meaning, using の instead of が.
The phrase originates from the idea that a 'bug' (虫) inside a person represents their true nature or desires. '虫がいい' literally means 'the bug is good,' implying that one's inner self is conveniently self-serving. The exact historical derivation is uncertain, but it is a common idiomatic expression.