当 hit the target

I hit the target of your TOE. The weapon is this sputum.

The three cute baby birds hit the pig right on the snout.

for realz. ★★★★★
本 (book / the real) + 当 (hit the target) = 本当 (for realz.)

appropriate ★★★★☆ JERK
適 (suitable) + 当 (hit the target) = 適当 (appropriate)

appropriate, as in an appropriate gift. However, 適当　also means irresponsible! Doing something without considering the consequences. 適当な人間だ！ “He's irresponsible. He'll say anything that pops into his head.”

natural, obvious ★★★☆☆
当 (hit the target) + 然 (nature) = 当然 (natural, obvious)

just, natural, deserved - although it's often used like 'That's obvious, isn't it?'

that day . . . ★★☆☆☆
当 (hit the target) + 日 (sun, day) = 当日 (that day . . .)