Noun and の adjective
こっかく
ガッシリした骨格の男性がタイプです。
I like a man with a sturdy build.
昨日は、この記事の骨格をまとめ終えました。
Yesterday, I completed an outline for this article.
コーラが骨格の発育に悪影響を与えるという噂は本当ですか？
Is the rumor that cola is detrimental to skeletal development true?
The status of your bones (aka how they're all arranged and put together) equals your skeleton. That bone status is lookin' good on you!
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. Just note that こつ changes to こっ.