noun
expert; skilled person
A somewhat formal or literary term for a person who has attained mastery through long practice. Often used in contexts like martial arts, traditional crafts, or professional skills.
彼は剣道の練達の士として知られている。
He is known as an expert in kendo.
この工房には陶芸の練達の士が集まっている。
This workshop gathers skilled masters of pottery.
熟練者 is a neutral, modern term for a skilled or experienced person. 練達の士 carries a slightly more classical or dignified tone.
Compound of 練達 (rentatsu, 'proficiency, mastery') + の (no, possessive particle) + 士 (shi, 'person, gentleman'). The exact historical derivation is uncertain, but the phrase follows a classical pattern for describing a person of a certain quality.