Supplanter or Saint James
Deago is a rare phonetic variant of the Spanish name Diego. It is ultimately derived from the Hebrew name Jacob via the Latin Sanctus Iacobus, meaning supplanter or held by the heel.
Less common today
Deago isn't in the latest US Top 1000. It last peaked at #5,044 in 2006.
US births per 5-year period, 1990βpresent (SSA data).