Chiefly dialectal US; intransitive verb meaning 'to rear, rise up' (esp. of an animal); also colloquial with 'to' indicating eagerness ('raring to go').
Definitions
To rise up or stand on the hind legs, especially said of a horse; to rear.
The startled stallion rared back, almost throwing its rider.
Followed by 'to'; to be extremely eager or enthusiastic (colloquial).
The children were raring to go as soon as the bell rang.