Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
con-tempĕro, āvi, ātum, 1, v. a., to moderate or temper by mixing (very rare; perh. not ante-Aug.): cantharum mulso, App. M. 10, p. 246, 34; so Veg. Art. Vet. 6, 9, 7; Marc. Emp. 16; Apic. 4, 2.