Grass is growing on the roadside.
noun
Archaic slang for a ninja, derived from the idea of hiding in the grass.
昔の隠語で、忍者を「草」と呼ぶことがあった。
In old slang, ninja were sometimes called 'kusa'.
noun
Modern slang for marijuana, from the resemblance to grass.
あいつは草を吸っているらしい。
I heard that guy smokes weed.
prefix
not genuine; substandard; makeshift
Prefix used to indicate something is makeshift, inferior, or not the real thing. Common in compounds like 草野球 (pickup baseball) or 草競馬 (local horse race).
週末は草野球を楽しんでいる。
I enjoy pickup baseball on weekends.
expression
Internet slang for laughter, derived from multiple 'w' characters (from 笑う) looking like grass. Used as an expression of amusement.
See also: ｗ
その動画、マジで草。
That video is seriously LOL.
草生えるわ。
That's hilarious.