Cops are on the hunt for a dapper-but-deadly young man who fatally stabbed a 66-year-old in Hell’s Kitchen during an argument last week, authorities said.

The suspect was caught on surveillance tape plunging a knife into the chest and back of Timothy Caughman near the corner of Ninth Avenue and West 36th Street at around 11:30 p.m., according to police.

He was suited up in a large black overcoat, brown dress shoes and dark-colored pants, cops said.

Caughman walked for about a block after the stabbing and staggered into the Midtown South Precinct, looking for help. He died hours later after being rushed to a nearby hospital.

Police sources said Caughman, who had prior run-ins with cops, was refusing to talk to police about the incident and acting combative before his death.

A witness told The Post that he had been arguing with the suspect on the street about something when the drama unfolded, though it was unclear. She said the man who stabbed Caughman fled on foot towards 8th Avenue before disappearing.

Police described him as a white male with blonde hair.