An absurdity is a thing that is extremely unreasonable, so as to be foolish or not taken seriously, or the state of being so. "Absurd" is an adjective used to describe an absurdity, e.g., "this encyclopedia article is absurd." It derives from the Latin absurdum meaning "out of tune", hence irrational. The Latin surdus means "deaf", implying stupidity. Absurdity is contrasted with seriousness in reasoning. In general usage, absurdity may be synonymous with ridiculousness and nonsense. In specialized usage, absurdity is related to extremes in bad reasoning or pointlessness in reasoning; ridiculousness is related to extremes of incongruous juxtaposition, laughter, and ridicule; and nonsense is related to a lack of meaningfulness.