All 6 Uses of

competent
in
Tom Jones, by Henry Fielding

She had lived several years a servant with a schoolmaster, who, discovering a great quickness of parts in the girl, and an extraordinary desire of learning—for every leisure hour she was always found reading in the books of the scholars—had the good-nature, or folly—just as the reader pleases to call it—to instruct her so far, that she obtained a competent skill in the Latin language, and was, perhaps, as good a scholar as most of the young men of quality of the age.†
Book 1

competent = sufficiently capable

Above all others, men of genius and learning shared the principal place in his favour; and in these he had much discernment: for though he had missed the advantage of a learned education, yet, being blest with vast natural abilities, he had so well profited by a vigorous though late application to letters, and by much conversation with men of eminence in this way, that he was himself a very competent judge in most kinds of literature.†
Book 1

From which she had attained a very competent skill in politics, and could discourse very learnedly on the affairs of Europe.†
Book 6 *

A competent knowledge of history and of the belles-lettres is here absolutely necessary; and without this share of knowledge at least, to affect the character of an historian, is as vain as to endeavour at building a house without timber or mortar, or brick or stone.†
Book 9

Nay, the very children, the youngest, which is not two years old, excepted, feel in the same manner; for they are a most loving family, and, if they had but a bare competency, would be the happiest people in the world.†
Book 13

Definitions:

(1) (competent)
capable (able to do something in a generally satisfactory manner) -- sometimes specifically to have legal capability
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

In the field of law, competent has the specialized meaning of being legally qualified to do something such as to be mentally fit to make reasonable decisions; or to have jurisdiction or authority to take an action.

In classic literature, a competency can refer to having an income or assets to support living expenses.