You probably already know the French words for “work”: le travail (noun) and travailler (verb). (By the way, it is interesting to note that these words come from a Latin word denoting a torture instrument.) However, they have colloquial synonyms that are used at least as frequently.
Bosser is very often used instead of travailler.
Laisse-moi tranquille, je bosse !
Leave me alone, I’m working!
Je bosse dans l’informatique.
I work in IT.
Je suis crevé, j’ai bossé toute la journée.
I am exhausted, I worked all day long.
The second word, le boulot, means “work” and “job”. You can use it anytime you would use travail. It happens to sound exactly like bouleau, an unrelated word meaning “birch”.
J’ai une tonne de boulot, je suis débordé.
I have loads of work, I am overwhelmed.
Beau boulot !
Ma mère a trouvé un nouveau boulot.
My mother found a new job.
There is another synonym I can mention: le taf (and the corresponding verb, taffer). Apparently, it is an acronym from travail à faire (“work to do”). I think it’s a recent word: I never heard it when I was a child and it seems to me that it just appeared at some point in the last decade (although it is probably older than this). I don’t use it, but it is quite common among young people.
Désolé, je peux pas venir, j’ai du taf.
Sorry, I can’t come, I have work to do.
Listen to the examples: