Fail-deadly is an origin trait in Destiny 2 that can appear on 6 weapons. There is also an enhanced version with a stronger effect.
What Fail-deadly does
Dealing damage grants a stacking bonus to magazine size, target acquisition, and range until your next final blow with this weapon.
Enhanced version
Dealing damage grants an improved stacking bonus to magazine size, target acquisition, and range until your next final blow with this weapon.
