TASK DEFINITION: You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For consistency, answers should be in all lower cased letters.
PROBLEM: Category: CURRENT EXPRESSIONS 
Clue: If you're engaging in wishful thinking, you may want to perform this type of "check"

SOLUTION: a reality check

PROBLEM: Category: ENDS IN "FF" 
Clue: The heaviest of dog breeds, it can exceed 180 pounds

SOLUTION: mastiff

PROBLEM: Category: GYPSIES, TRAMPS & THIEVES 
Clue: Gypsies are called gypsies in the mistaken belief that they came from this African country

SOLUTION:
egypt