In poker, four out of five cards needed to make a straight if the middle number is the one missing.
Opposite of open-ended (four cards in a row that will make a straight with either low or high card).
A gut-shot straight draw is less likely to suceed because there are only four cards that can help you. Open-ended straight draws have better odds because there are eight cards that can make your straight.
Gut-shot = 2,3,_,5,6 or 9,10,_,Q,K
Open-ended = _,3,4,5,6,_ or _,10,J,Q,K,_