imperceptible

a.感觉不到的

impeccable, impeccably, impecunious, impecuniously, impecuniousness, impedance, impede, impediment, impedimenta, impel, impend, impending, impenetrability, impenetrable, impenetrably, impenitence, impenitent, impenitently, imperative, imperatively, imperceptibly, imperfect, imperfection, imperfectly, imperial, imperialism, imperialist, imperialistic, imperially, imperil, imperious, imperiously, imperiousness, imperishable, impermanence, impermanent, impermeability, impermeable, impermissible, impersonal,