1. superlative form of sour; having the most sharp, acidic taste
2. superlative form of sour; most bad-tempered or unfriendly in mood or manner

Examples

• This is the sourest lemon I’ve ever tasted.
• The green apples were the sourest ones in the basket.
• He had the sourest expression on his face after losing the game.
• She gave me the sourest look when I interrupted her.
• Of all the pickles, these are the sourest.
• His sourest mood always came out on Monday mornings.