Fetching details from the dictionary...

suitable; proper; appropriate; adequate; fit; fair
perfunctory; half-minded; sloppy; lazy; careless; noncommittal; unreliable; irresponsible; haphazard
適当な言葉が見つからない。
I can't find the right words.
適当な仕事ぶりで部長に叱られた。
His perfunctory work style got him scolded by the manager.
好きなものを適当に選んでください。
Please choose appropriately.