(stāl) adjective
1. Having lost freshness; slightly changed or deteriorated by standing, as air, vapid wine or beer, old bread, etc.
2. Lacking in interest from age or familiarity; worn out; trite: a stale joke.
3. In poor condition from prolonged activity, as from over-study or, in athletics, from overtraining: especially in the phrase gone stale.
4. Inactive; dull: said of a stock market after a period of overactivity.
5. Law In courts of equity, impaired in legal force, due to long neglect in pressing or asserting a claim or to a change in the condition or situation of the parties. See synonyms under TRITE.
—v.i. staled, stal·ing To become stale or trite. [Origin uncertain]
—stale′ly adverb
—stale′ness noun

(stāl) noun
The urine of cattle or horses.
—v.i. staled, stal·ing To urinate: said of horses and cattle. [Prob. <MLG stal horse urine]

(stāl) noun Obs.
1. A prostitute; drab.
2. A snare; trap.
3. Concealment; stealth; also, theft. [? <AF estale, estal a decoy]