Словарь синонимов английского языка - imperceptible

(adj) 1. invisible, indiscernible, indistinguishable, undetectable, obscure, vague, ill-defined; inaudible: The differences between the twins are imperceptible. 2. indistinct, unclear, unnoticeable, slight, subtle, inconsiderable, inappreciable, minute, tiny, slight, minuscule, infinitesimal, microscopic: Her only besponse was an imperceptible flicker of her eyelid.