Adjectives
Mauvais is usually an adjective that modifies a noun and means bad, mean, wrong, etc. Mal means bad, ill-at-ease, immoral, etc., and can only be used as an adjective with copular (state-of-being) verbs such as être (to be) and se sentir (to feel).
| Il a de mauvais yeux. | He has bad eyes (can't see). | C'est mal de dire ça. | It's bad (wrong) to say that. | |
| C'est une mauvaise excuse. | That's a bad/poor excuse. | Il est mal à l'école. | He is (feels) uncomfortable at school. | |
| Il est mauvais acteur. | He's a bad actor. | Je suis mal avec eux. | I'm on bad terms with them. | |
| un mauvais numéro | wrong number | Il va mal ce soir. | He is very ill tonight. | |
| une mauvaise personne | bad/malicious person | |||
Adverbs of manner
Mal is usually an adverb meaning poorly, badly, improperly, etc. It can also be used in front of a past participle in order to give that verb a negative meaning. Mauvais, in the rare instances where it is used as an adverb (see adverbial adjectives), means bad.
| J'ai mal dormi. | I slept poorly. | Cela sent mauvais. | That smells bad. | |
| Il parle mal le français. | He speaks French poorly. | Il fait mauvais. | The weather is bad. | |
| La porte ferme mal. | The door doesn't close properly. | |||
| Ce travail est mal fait. | This work is badly done. | |||
| Il y a pas mal de gens. | There are quite a few people. | |||
Nouns
Le mauvais means bad/negative part or bad in the general sense of evil, while le mal (plural maux) refers to a difficulty, evil, or (with the verb avoir) pain.
| Je n'ai pas mangé le mauvais. | I didn't eat the bad part. | J'ai du mal à le voir. | I'm having trouble seeing it. | |
| Il ne parle que du mauvais. | He only talks about the bad side. | J'ai mal à la tête. J'ai un mal de tête. |
I have a headache. | |
| les mauvais | the wicked | J'ai des maux de tête. | I get headaches. | |
| le Mauvais | the Devil | le mal du pays | homesickness | |
| les maux de société | societal ills |
| En résumé | |||
| Mauvais | Mal | ||
| adjective | bad (with noun) | bad (with copular verb) | |
| adverb | bad | badly | |
| noun | bad part | evil(s) | |
Quiz: Mauvais vs mal, bon vs bien
