grass up

Verb

UK slang

(UK, slang) To betray by informing on.

Japanese Meaning

密告する：他人の秘密や不正行為を裏切って当局などに知らせる行為。 / 告げ口する：仲間やグループ内の不正を暴露する、他者に情報を漏らす行為。

He threatened to grass up his co-worker unless they handed over the missing files.

彼は、行方不明の書類を渡さなければ同僚を密告すると脅した。

Sense（1）

(UK, slang) To betray by informing on.

My sister grassed me up to the caretaker! She thought she was doing me a favour — by grassing me up she was sure he'd let me off.

grasses up

（ present singular third-person ）

grassing up

（ participle present ）

grassed up

（ participle past ）

grassed up

（ past ）