Definition of coast:
the shore of a sea or ocean
a slope down which sleds may coast; "when it snowed they made a coast on the golf course"
the area within view; "the coast is clear"
the act of moving smoothly along a surface while remaining in contact with it; "his slide didn't stop until the bottom of the hill"; "the children lined up for a coast down the snowy slope"
move effortlessly; by force of gravity