noun which may take the genitive case particle 'no', noun
high-necked; turtleneck
Describes clothing with a high neckline, such as turtlenecks or high-neck sweaters. Often used as a noun or with の to modify another noun.
今日は寒いからハイネックのセーターを着てきた。
It's cold today, so I wore a turtleneck sweater.
あの店にはハイネックのカットソーがたくさんある。
That shop has a lot of high-neck cut-and-sew shirts.