grass on/up
phrasal verb
grassed on/up; grassing on/up; grasses on/up
British slang
: to tell the police about the criminal activity of (someone)
He refused to grass on his friends.
Someone grassed him up.
Cite this Entry
“Grass on/up.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/grass%20on%2Fup. Accessed 30 Apr. 2025.
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Merriam-Webster unabridged
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