Attai = "opportune"

 1) a Judaite, grandson of Sheshan the Jerahmeelite by daughter Ahlai
    whom he gave in marriage to Jarha, his Egyptian slave; his grandson
    Zabad was one of David's mighty warriors
 2) one of the lion-faced warriors of Gad, captains of the host, who
    joined David in the wilderness
 3) the 2nd son of king Rehoboam of Judah by Maachah, the daughter of
    Absalom