1.
suitable, appropriate, proper
Fitting or appropriate for a particular purpose or situation.
この部屋は会議に適当だ。
This room is suitable for meetings.
適当な大きさに切ってください。
Please cut it to an appropriate size.
適当な運動は健康に良いと言われている。
It is said that moderate exercise is good for your health.
この仕事に適当な人を探しているのですが、なかなか見つかりません。
I'm looking for a suitable person for this job, but I can't seem to find one.
子供の年齢に適当な本を選んであげたいのですが、どれがいいか教えてもらえますか。
I'd like to choose a book that's appropriate for my child's age — could you tell me which one would be good?
2.
random, sloppy, half-hearted
Done without much thought or care; careless or irresponsible (often negative).
適当なことを言うな。
Don't say random things.
適当に答えないでください。
Please don't answer carelessly.
適当な理由をつけて断ってしまった。
I made up some random excuse and turned it down.
仕事を適当にやっていると、いつか大きな失敗をするよ。
If you keep doing your work sloppily, you'll make a big mistake someday.
あの人はいつも適当なことを言うから、誰も本気で話を聞かなくなってしまった。
That person always says random things, so nobody takes what they say seriously anymore.
適当 has two nearly opposite meanings depending on context.
SENSE 1 (positive): Suitable, appropriate
- 適当な人: suitable person
- 適当な値段: reasonable price
SENSE 2 (negative): Careless, sloppy
- 適当にやる: to do carelessly
- 適当な仕事: sloppy work
SIMILAR WORDS:
- 適切: appropriate (always positive, more formal)
- いい加減: half-hearted, irresponsible
Context is key to understanding which meaning is intended.