Is there a difference in register between saying:
He failed to show for his appointment
When will the bus show?
He failed to show up for his appointment
When will the bus show up?
Informal. to be present or keep an appointment; show up: He said he would be there, but he didn't show. Random House
Slang To make an appearance; show up: didn't show for her appointment. AHD
: to put in an appearance; arrive CED
: to make an appearance; show up Random House Kernerman Webster's College Dictionary
: put in an appearance; failed to show M-W
show or show up Informal: to arrive in a place where people are expecting you; We didn’t think Austin would show. McMillan Dictionary
(mainly US) to show up CDO
Informal Arrive for an appointment or at a gathering: only two waitresses showed up for work; her date failed to show ODO
also show up; Informal; especially American English: to arrive at the place where someone is waiting for you: I went to meet Hank, but he never showed. LDOCE