unconscionable: When used for unconscionably is a bad provincialism. Used also by the illiterate instead of uncommonly; as, "She is an unconscionable handsome girl"—this is bad English.
under: Much philological nonsense has been written in disapproval of the expression "under his signature," for which "over his signature"—that "preposterous conceit," as Gould aptly terms it—is suggested as a substitute. But it is clear that the expression is elliptical, and means "under sanction or authority of his signature." "Under oath" is good enough to impress upon an unwilling and prevaricating witness the distinction between perjury and a lie, and that although he does not physically lie under the oath.
understand should not be used as an expletive with interrogatory inflection, as a contraction of "Do you understand?" There is no excuse for this nor for its objectionable iteration. Avoid such absurdities as: "Grammar, understand, is the science that treats of the principles, understand, that govern the correct use of language," etc. See is also misused in the same manner.
unique: As this word implies "being the only one of its kind" it should never be preceded by "very" which implies degree. On this subject the Standard Dictionary says: "We may say quite unique if we mean absolutely singular or without parallel but we can not properly say very unique."