From Longman Dictionary of Contemporary Englishstick insectˈstick ˌinsect noun [countable] British English HBIa long thin insect that looks like a small stick young models who look like stick insects (=are very thin)
Examples from the Corpus
stick insect• He was built like a basketball player; tall and as thin as a stick insect.• When I was young I was like a stick insect, then at fourteen or fifteen I put on weight.• The initial resemblance of the ancestral stick insect to a stick must have been very remote.• One of them, anyway - the stick insect couldn't have escaped. 