'At best' definitions:

Definition of 'at best'

From: WordNet
adverb
Under the best of conditions; "at best we'll lose only the money" [syn: at best, at the best] [ant: at the worst, at worst]

Definition of 'At best'

From: GCIDE
  • Best \Best\, n. Utmost; highest endeavor or state; most nearly perfect thing, or being, or action; as, to do one's best; to the best of our ability. [1913 Webster]
  • At best, in the utmost degree or extent applicable to the case; under the most favorable circumstances; as, life is at best very short.
  • For best, finally. [Obs.] "Those constitutions . . . are now established for best, and not to be mended." --Milton.
  • To get the best of, to gain an advantage over, whether fairly or unfairly.
  • To make the best of. (a) To improve to the utmost; to use or dispose of to the greatest advantage. "Let there be freedom to carry their commodities where they can make the best of them." --Bacon. (b) To reduce to the least possible inconvenience; as, to make the best of ill fortune or a bad bargain. [1913 Webster]