The gutshot or inside straight draw refers to a drawing hand missing one middle card to complete a straight.
It's the opposite of an open-ended straight draws where two different cards can complete the straight. Gutshot draws are by definition, less favorable than open-ended straight draws.
A player holds 2♥2♥ and the board displays 2♥2♥2♥.
The only card missing to complete a straight is a 6.