shirt tail
From Longman Dictionary of Contemporary EnglishRelated topics: Clothesshirt tailˈshirt tail noun [countable] DCCthe part of a shirt that is below your waist and is usually inside your trousersExamples from the Corpusshirt tail• But a long shirt tail flopped down around his thighs.• I stuffed my shirt tail back into my trousers and tried to straighten my tie.