someone who is bull-headed is determined to do exactly what they want to do, and does not think about what other people want.
He's completely bull-headed. I asked him not to throw out that old table, but he did it anyway.
bull-headed
Inflexible; stubborn; overly willful or obstinate. Our son is so bull-headed. Once he's made up his mind about something, there's no way anyone can change it!We've got a bull-headed new boss in the office who thinks her way of doing things is the only correct one.
bullheaded
mod. stubborn. You are the most bullheaded man I’ve ever known.