Fall short and Fall flat

Fall short verb - Fail to meet (expectations or standards).

Fall flat and fall short are semantically related in fail topic. In some cases you can use "Fall flat" instead a verb phrase "Fall short", when it comes to topics like fail miserably, be unsuccessful, fail to attain goal.

Fall flat verb - Fail utterly; collapse.

Fall short and fall flat are semantically related in fail topic. You can use "Fall short" instead a verb phrase "Fall flat", if it concerns topics such as fail miserably, be unsuccessful, fail to attain goal.