Flailing, or abare (from the Japanese term meaning ‘struggle’ or ‘act unruly’, etc.), refers to using a rapid-fire normal move in its rapid-fire capacity; less calculating than zoning, it is usually intended to keep an approaching opponent away.
Typical flailing involves using fast pokes to keep away throw attempts.
With characters you have trouble dealing with and in close combat, it is an effective tool to have, but it can easily be stuffed if the opponent has moves with invincibility, autoblock, and so forth. It can also get smashed if the opponent knows just how to delay their offense, so flailing is not always the most successful strategy.
Very good or lucky flailing can segue into a combo.