To warp is to bend, twist, or otherwise become misshapen. Wooden furniture left outside in the rain will often warp from the moisture.
Getting wet makes some things warp, while plastic has a tendency to warp in the hot sun. Sometimes people use the word colloquially to mean "have a bad or distorting influence on," as when a politician insists that video games warp kids' minds. In weaving, the warp is all of the threads running one direction — the ones that are woven over and under the warp are called the weft.