Origine of a phrase

[arty7774]

Does any one out there know who the phrase " to grass" as in informing about a person came about.
Where and why was it first used.

Thanks in advance.

Arty7774

[Tefler]

The word 'grass' meaning an informer or the act of informing dates back only to the 1930s. The probable source is the word 'grasshopper', the idea being that the 'grass' went to the 'copper' with his information.

[Quizmonster]

'Nark' comes from the Romany word 'nak', meaning 'nose' - obviously involving someone 'sniffing out' information. It is about a century older than 'grass' in the passer-on of information sense.
The rhyming slang involved in 'grass' is the one suggested by Tefler above, since 'grasshopper' rhymes with 'copper'. In other words, policemen in 19th century London were themselves called 'grasshoppers'. Not until much later did the 'grass' idea peel away and attach itself to the informer rather than the one being informed.