不良 bùliáng bad
bad; harmful; unhealthy; (of a device, connection, material etc) defective; faulty
How to remember 不良: 不 not + 良 good = bad.
Characters
How it is used
- Bad/harmful/undesirable - attributive, formal register. 不良习惯 (bùliáng xíguàn) bad habits; 不良影响 (bùliáng yǐngxiǎng) a negative influence.
- Also 'faulty/defective': 消化不良 (xiāohuà bùliáng) indigestion; 接触不良 (jiēchù bùliáng) a bad connection.
- 不良 modifies nouns in a formal/institutional way (不良记录 a bad record), unlike casual 不好 (bù hǎo).