What was Apollo 17's lunar module called?

Apollo 17's lunar module was called Challenger.

Challenger carried commander Eugene Cernan and lunar module pilot Harrison Schmitt to the Taurus–Littrow valley in December 1972. The spacecraft's descent stage served as a base for surface operations, while its ascent stage returned the two astronauts to lunar orbit.

Command module pilot Ronald Evans remained aboard America, photographing the Moon and conducting orbital observations. Apollo 17 was the final crewed lunar landing of the Apollo program and the only one with a trained professional geologist, Schmitt, on the surface.

Challenger is sometimes confused with Orion, Apollo 16's lunar module, or Falcon, Apollo 15's. The name was later reused for NASA's Space Shuttle Challenger, which was a completely different spacecraft.