lawn,
sward, grassland, meadow, pasture, prairie, greensward (archaic or
literary)
informant,
informer, traitor, snitch (slang), squealer (slang disapproving), narc (slang),
supergrass (UK, informal)
inform,
betray, give away, snitch (slang), squeal (slang disapproving), grass up (UK,
slang), blow the whistle, sneak
crabgrass, bamboo, beach grass,
bluegrass, bulrush, couch grass, esparto, fescue, Kentucky bluegrass, lyme
grass, marram, meadow fescue, pampas grass, reed, rye grass, spinifex, sugar
cane, sword grass, timothy