Also, have got to. Be obliged to, must. For example, We have to go now, or He has got to finish the paper today. The use of have as an auxiliary verb to indicate obligation goes back to the 16th century; the variant using got dates from the mid-1800s.
Examples from the Web for have to
You git that Owens if you have-to haze him to hell and back!The Flying U's Last Stand
B. M. Bower