admirer (n.)

early 15c. (implied in admired), "regard with wonder, marvel at," from Old French admirer "look upon, contemplate" (correcting earlier amirer, 14c.), or directly from Latin admirari "regard with wonder, be astonished," from ad "to, with regard to" (see ad-) + mirari "to wonder," from mirus "wonderful" (see smile (v.)). The sense has gradually weakened toward "regard with pleasure and esteem," but for a time they overlapped.

Doe not admire why I admire :

My fever is no other's fire :

Each severall heart hath his desire ;

Els proof is false, and truth a lier.

[Campion, "And would You Faine the Reason Knowe," "Rosseter's Booke of Ayres Part II," 1601]

Related: Admiring; admiringly.