The Japanese word for grass is
草

くさ - kusa

Japanese Definition

草
1. n. grass
(synonyms, ja, 芝生, tr1=shibafu, q1=in reference to a lawn)
草を刈る - to cut grass
2. n. a weed
3. n. a herb
(synonyms, ja, ハーブ, tr1=hābu, 薬草, tr2=yakusō, q2=medicinal, 香草, tr3=kōsō, q3=cooking)
4. n. a scout, a spy (from the way one would hide in the grass to observe enemy troops)
5. n. (metaphor slang) pubic hair
6. prefix. a fake, a mimic, not the real thing
草蜉蝣 - a lacewing fly (literally, “fake or mimic dragonfly”, from the visual resemblance)
7. prefix. amateur, small-time
草野球、草競馬 - amateur or pick-up baseball, small-time horse-racing
8. n. grass
9. n. a draft, a rough copy
10. n. cursive, calligraphy in a running hand
11. n. something unofficial, an informal abbreviation or knock-off
12. n. (Internet slang) "grass", in reference to the expression w; LOLs
13. n. ====Phrase====
14. n. (ellipsis of ja, 草生える, tr=kusa haeru): (Internet slang) … it's hilarious
(synonyms, ja, 草生える, tr1=kusa haeru, 笑える, tr2=waraeru)
鯖%落ちてて草 - lol the server's down
下手すぎて草 - hilariously shitty
4日しかないのは草 - only 4 days left haha