1To become stronger or gain strength/intensity — used for winds, emotions, pressure, influence, etc. (intransitive).
台風の勢力が次第に強まっている。
The typhoon's strength is gradually increasing.
彼の自信が経験とともに強まった。
His confidence grew stronger with experience.
対立が強まると交渉が難しくなる。
When conflicts intensify, negotiations become more difficult.