The term CLIMBER'S RETURN TRIP is composed of two words, the first being CLIMBER and the second being RETURN TRIP. The crossword solution for the first word is DESCENT, which refers to the act of going down a mountain or other steep surface. The second word, RETURN TRIP, refers to the journey back from the mountain after the CLIMBER has descended. Together, the two words describe the journey of a CLIMBER who has gone up a mountain and is now returning back down.