strong point

noun

1. something at which one excels; forte

   tactfulness was never his strong point

Idioms and Phrases

Also, strong suit. An area in which someone or something excels, as in That beautiful lobby is the building's strong point, or Writing is her strong suit. The first term was first recorded in 1840; the variant alludes to various card games, in which it signifies the suit with the highest or most cards.