Unattach
To move an Equipment away from the creature it’s attached to so that the Equipment is on the battlefield but is not equipping anything. See rule 701.3d.

Unblockable
An attribute of a creature that precludes it from being blocked. See rule 700.5.

Unblocked Creature
An attacking creature once no creature has been declared as a blocker for it, unless an effect has caused it to become blocked. It remains an unblocked creature until it’s removed from combat or the combat phase ends, whichever comes first. See rule 509, "Declare Blockers Step."

Unearth
A keyword ability that lets a player return a creature card from his or her graveyard to the battlefield. See rule 702.81, "Unearth."

Unflipped
A default status a permanent may have. See rule 110.6 and rule 709, "Flip Cards." See also Flipped.

Unless
A word used to indicate a certain style of cost. See rule 117.12a.

Untap
To rotate a permanent back to the upright position from a sideways position. See rule 701.16, "Tap and Untap."

Untap Step
Part of the turn. This step is the first step of the beginning phase. See rule 502, "Untap Step."

Untap Symbol
The untap symbol in an activation cost means "Untap this permanent." See rule 107.6.

Untapped
A default status a permanent may have. See rule 110.6 and rule 701.16, "Tap and Untap." See also Tapped.

Upkeep Step
Part of the turn. This step is the second step of the beginning phase. See rule 503, "Upkeep Step."