How to say "self-serving" in Japanese

• 利己的りこてき
  na-adjectiveCovers the general sense of 'self-serving': acting in one's own interest with little regard for others. A straightforward term for describing a person, motive, or attitude, though the word itself is not especially common.
  利己的りこてきな行動こうどうをするべきではない。↗

  You ought not to act selfishly.
• がりがり
  na-adjectiveA mimetic word, normally written in kana, whose 'selfish' use is vivid rather than neutral; better known for other senses like gauntness or gnawing sounds, it is seldom the word you want for 'self-serving'.

For the general sense of 'self-serving' — acting in one's own interest — 利己的 is the straightforward choice, while 「がりがり」 is a mimetic word whose 'selfish' use is only a marginal option.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 利己的りこてきselfish
• がりがりselfish