Bust can be a verb, an adjective, or a noun. The past tense and past participle of the verb is either bust or busted.
used as a verb
If you bust something, you break or damage it so badly that it cannot be used. Note that you only use bust with this meaning in conversation. You do not use it in formal writing.
She found out about Jack busting the double-bass.
In informal English, if someone is busted, the police arrest them.
They were busted for possession of cannabis.
used as an adjective
In conversation, if you say that something is bust, you mean that it is broken or very badly damaged.
That clock's been bust for weeks.
Note that in American English, the adjective is busted not ‘bust’.
There he found a small writing table with a busted leg.
If a company goes bust, it loses so much money that it is forced to close down. You do not use this expression in formal English.
The company almost went bust in February.
used as a noun
A woman's bust is her breasts.
➜ See breast - bust - bosom