noun
one advantage; a merit
Often used in the set phrase 一得一失 (いっとくいっしつ, 'one gain, one loss') or in contexts weighing pros and cons. As a standalone noun it is somewhat formal and less common in casual speech.
この案には一得一失がある。
This plan has both an advantage and a disadvantage.
彼の提案にも一得はあると思う。
I think his proposal also has a merit.