Drying Up
Dry Up, Running Dry
Something that withers from thirst ends up drying up. If you let a plant dry up like this it might die if you don't water it soon.
こかつ
This is a jukugo word that uses the on'yomi readings of the kanji. You didn't learn this reading for 渇 yet, so here's a mnemonic to help you:
If all of your plants are drying up you should just give them to your cats (かつ). Cats love to play with dried up plants. At least they won't go to waste.
もうすぐ石油は枯渇する。
The petroleum will dry up very soon.