Shrivel in the heat is a term used to describe the process of plants and other organic matter drying out due to extreme heat. The two crossword solutions for this term are WILT (4 letters) and WITHER (6 letters). WILT is a verb that means to become limp or droop, usually due to lack of water or heat. WITHER is also a verb that means to dry up or shrivel, usually due to lack of water or heat. Both terms are used to describe the process of plants and other organic matter drying out due to extreme heat.