At all Meaning, Definition & Usage

  1. adverb in the slightest degree or in any respect
    in the least; the least bit.
    • Are you at all interested? No, not at all
    • was not in the least unfriendly

WordNet

Definitions
  1. . (a) In every respect; wholly; thoroughly. Obs. "She is a shrew at al(l)." Chaucer. (b) A phrase much used by way of enforcement or emphasis, usually in negative or interrogative sentences, and signifying in any way or respect; in the least degree or to the least extent; in the least; under any circumstances; as, he has no ambition at all; has he any property at all? "Nothing at all. " Shak. "It thy father at all miss me." 1 Sam. xx. 6 .

Webster 1913