안이해요 · 안이했어요 · 안이한 (+noun)
complacent, easygoing, lax
Example
문제를 너무 안이하게 생각하면 안 돼요.
You shouldn't think about the problem so complacently.
Word parts
안 comfortable+이 easy
Literally 'comfortable and easy' — too relaxed about something serious.
Good to know
Critical in tone: 안이한 대처 'a complacent response'; don't confuse with 용이하다 'easy to do'.