허술해요 · 허술했어요 · 허술한 (+noun)
careless, sloppy, loose; flimsy
Example
보안이 허술해서 개인 정보가 유출됐어요.
Security was so lax that personal information was leaked.
Good to know
Often about systems and plans: 관리가 허술하다 'management is lax'. Compare 허름하다 'run-down'.
Related words