long suit

noun

1. Cards.

   1. the suit in which the most cards are held in a hand.

   2. (in bridge) a suit in which four or more cards are held in a hand.

2. the quality, activity, endeavor, etc., in which one excels.

   Diligence is his long suit.

long suit

noun

1. 1. the longest suit in a hand of cards

   2. a holding of four or more cards of a suit

2. informal,  an outstanding advantage, personal quality, or talent

Word History and Origins

Origin of long suit¹

First recorded in 1875–80

Idioms and Phrases

One's strong point or advantage, as in Organizing has never been Nancy's long suit. This expression alludes to whist, bridge, and other card games in which holding numerous cards in a single suit may convey a strong advantage. [c. 1900]