Adonijah in Smiths Bible Dictionary

(my Lord is Jehovah). 1. The fourth son of David by Haggith, born at Hebron while his father was king of Judah. 2Sa 3:4 (B.C. about 1050.) After the death of his three brothers, Amnon, Chileab and Absalom, he became eldest son; and when his father's strength was visibly declining, put forward his pretensions to the crown. Adonijah's cause was espoused by Abiathar and by Joab the famous commander of David's army. [JOAB] His name and influence secured a large number of followers among the captains of the royal army belonging to the tribe of Judah, comp. 1Ki 1:5 and these, together with all the princes except Solomon, were entertained by Adonijah at the great sacrificial feast held "by the stone Zoheleth, which is by En-rogel." [EN-ROGEL] Apprised of these proceedings, David immediately caused Solomon to be proclaimed king, 1Ki 1:33,34 at Gihon. [GIHON] This decisive measure struck terror into the opposite party, and Adonijah fled to the sanctuary, but was pardoned by Solomon on condition that he should "show himself a worthy man." 1Ki 1:52 The death of David quickly followed on these events; and Adonijah begged Bath-sheba to procure Solomon's consent to his marriage with Abishag, who had been the wife of David in his old age. 1Ki 1:3 This was regarded as equivalent to a fresh attempt on the throne [ABSALOM; ABNER]; and therefore Solomon ordered him to be put to death by Benaiah. 1Ki 2:25 2. A Levite in the reign of Jehoshaphat. 2Ch 17:8 3. The same as Adonikam. Ne 10:16 [ADONIKAM]

Link: https://bible-history.com/smiths/A/Adonijah/