Lewis & Short

ē-marcesco, -marcui, 3, v. inch. n., to wither away (very rare).
Trop., to dwindle away, disappear: auctoritas, Plin. 15, 29, 36, § 121: refugium, Hier. Ies. 5, 17, 4: cor meum, fainted, Vulg. Isa. 21, 4 al.† † emarcus, i [a Gallic word], a kind of vine, producing a wine of middling quality, Col. 3, 2, 25 (called also marcus, Plin. 14, 2, 4, § 32).