From Quake Wiki
float walkmove(float yaw, float dist)
Moves the entity referenced by self in the direction and distance specified.
yaw- The direction that the entity will move in.
dist- The distance that the entity will move in.
- Returns TRUE if the movement completed successfully, and FALSE if it did not. The entity's position is reverted if the move is unsuccessful.
walkmove, unlike movetogoal, does not affect the entity's angles so, in the case of monsters, it causes them to slide around. Also unlike movetogoal, walkmove does not affect vertical position at all and will not match heights with enemies.