not capable of being precisely or readily described; not easily put into words; "an indefinable feeling of terror"; "an abstract concept that seems indefinable"
defying expression or description; "indefinable yearnings"; "indescribable beauty"; "ineffable ecstasy"; "inexpressible anguish"; "unspeakable happiness"; "unutterable contempt"; "a thing of untellable splendor"
the fusion of originally different inflected forms (resulting in a reduction in the use of inflections)
the union (or attempted fusion) of different systems of thought or belief (especially in religion or philosophy); "a syncretism of material and immaterial theories"