肉にく付づきが良よい

also: にくづきがいい

Meanings

1

expression, i-adjective (yoi/ii class)

plump; well-fleshed; stout

Describes a person or animal with a good amount of flesh, often in a positive or neutral way. Used for healthy plumpness rather than obesity.

かれ

は

肉にく

付づ

き

が

いい

体たい

型けい

を

し

て

いる

。

He has a well-fleshed build.

太ふとっている
太っている means 'fat' or 'overweight' and can carry a negative nuance, while 肉付きが良い is more neutral or positive, focusing on healthy fleshiness.
ぽっちゃり
ぽっちゃり is a casual, often affectionate term for chubbiness, whereas 肉付きが良い is a more descriptive, standard expression.

Compound of 肉付き (nikuzuki, 'fleshiness') + が (subject marker) + 良い/いい (yoi/ii, 'good'). The phrase literally means 'the flesh attachment is good'.