ハイネック

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.

• 今日きょうは寒さむいからハイネックのセーターを着きてきた。

  It's cold today, so I wore a turtleneck sweater.

• あの店みせ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.