An (∞,1)-functor F:C→D is fully faithful if, when modeled as a functor of simplicially enriched categories the induced functor on homotopy categories
h F : h C \to h D
of Ho Top-enriched categories is fully faithful, i.e. if the morphisms
h F_{X,Y} : h C(X,Y) \to h D(F(X), F(Y))
are isomorphisms in Ho Top for all objects X,Y.