Trigger Creep
Also: Creep
Unwanted trigger movement after the wall and before the break, felt as a mushy drag that makes the moment of release hard to predict.
Creep is the perceptible travel that happens after the trigger reaches the wall but before the sear actually releases. Instead of a clean stop followed by a crisp break, the finger drags through a soft, gritty zone while pressure climbs, and the shooter cannot feel exactly when the shot will go. That uncertainty pulls the eye off the reticle and invites the rifle to move right as the shot breaks.
A small amount of creep is normal on a working trigger pull, but precision shooters chase a break with almost none of it. Smoothing or eliminating creep, usually through better engagement geometry on a quality single-stage trigger, is one of the most valuable upgrades a long-range rifle can get. Creep should not be confused with overtravel, which is the slack that continues after the sear has already let go.