expression, suru verb (irregular)
devote oneself to; make a point of
Used when someone concentrates on a single activity or makes something their main focus, often with a sense of deliberate choice.
彼は研究をもっぱらにしている。
He devotes himself to research.
最近
Lately I've been making health management my main focus.
expression, suru verb (irregular)
do as one pleases; act selfishly
Carries a negative nuance of self-centered behavior; often implies ignoring others' wishes or social norms.
彼は会議で自分の意見をもっぱらにして、他の人の話を聞かなかった。
He pushed his own opinion at the meeting and didn't listen to others.
子どもがわがままをもっぱらにする時期もある。
There are times when children act entirely selfishly.