The Hebrew proper name Abiyhuʾ (אֲבִיהוּא) means "He is my Father" or "My Father is He" — from ab (father) and hu (he). The name appears most notably as the name of Aaron's second son, a priest ordained alongside his father, his brother Nadab, and seventy elders of Israel (Exodus 24:1). Abihu and Nadab were struck dead by God for offering unauthorized fire before the LORD (Leviticus 10:1-2).
The account of Abihu and Nadab is one of the most sobering in the Torah. Their offense — offering esh zarah, "unauthorized" or "strange fire" — came immediately after the inaugural consecration of the tabernacle worship. The precise nature of their sin has been debated (drunk worship? Wrong timing? Wrong incense? Self-invented ritual?), but the theological point is clear: God's holiness is not negotiable. The name Abihu — "He is my Father" — is deeply ironic in its context: these men knew God as Father but did not approach Him on His terms. God told Aaron through Moses: "Among those who approach me I will be proved holy; in the sight of all the people I will be honored" (Leviticus 10:3). Nearness to God requires reverence, not presumption.