Common: 1. "Как-нибудь" (like "somehow") 2. "Нехорошо" (like "not good") There are many synonyms depending on what meaning you want to emphasize, e.g. lack of quality, speed of doing, etc. - "Спустя рукава" (in the meaning if you don't want to make any effort).

Do you need to know the synonyms in the formal speach?