sour
  Pronunciation: (sour, sou'ur), [key]    — adj., n., v. -er, -est, 
  
 
—adj. - having an acid taste, resembling that of vinegar, lemon juice, etc.; tart.  
- rendered acid or affected by fermentation; fermented.  
- producing the one of the four basic taste sensations that is not bitter, salt, or sweet.  
- characteristic of something fermented: a sour smell. 
- distasteful or disagreeable; unpleasant.  
- below standard; poor.  
- harsh in spirit or temper; austere; morose; peevish.  
- (of soil) having excessive acidity.  
- (of gasoline or the like) contaminated by sulfur compounds.  
- off-pitch; badly produced: a sour note. 
 
—n. - something that is sour.  
- any of various cocktails consisting typically of whiskey or gin with lemon or lime juice and sugar and sometimes soda water, often garnished with a slice of orange, a maraschino cherry, or both.  
- an acid or an acidic substance used in laundering and bleaching to neutralize alkalis and to decompose residual soap or bleach.  
 
—v.i. - to become sour, rancid, mildewed, etc.; spoil: Milk sours quickly in warm weather. The laundry soured before it was ironed. 
- to become unpleasant or strained; worsen; deteriorate: Relations between the two countries have soured. 
- to become bitter, disillusioned, or disinterested: I guess I soured when I learned he was married. My loyalty soured after his last book. 
- (of soil) to develop excessive acidity.  
 
—v.t. - to make sour; cause sourness in: What do they use to sour the mash? 
- to cause spoilage in; rot: Defective cartons soured the apples. 
- to make bitter, disillusioned, or disagreeable: One misadventure needn't have soured him. That swindle soured a great many potential investors. 
 
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.