1. Bitter or scornful
   "the face was saturnine and swarthy, and the sensual lips...twisted with disdain" 
2. Showing a brooding ill humour
   "a saturnine, almost misanthropic young genius"
   - dark, dour, glowering, glum, moody, morose, sour, sullen

See also: ill-natured, sarcastic

• collared pika
• collarless
• collate
• collateral
• collateral damage
• collateral fraud
• collateralise
• collateralize
• collaterally
• collation
• collator
• colleague
• collect
• collect call
• collectable
• collectanea
• collected
• collectedly
• collectible
• collecting
• collection
• collection plate
• collective
• collective agreement
• collective bargaining