suitable person; fit person; the fit
Refers to a person who is well-suited or qualified for a particular role, task, or condition. Often used in contexts of selection, adaptation, or survival of the fittest.
この仕事の適者を探している。
We are looking for a suitable person for this job.
適者生存
Survival of the fittest is a fundamental principle of evolution.
survival of the fittest
Compound of 適 (suitable) and 者 (person). The exact historical derivation is uncertain, but the word follows a common Sino-Japanese pattern for forming agent nouns.