This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
骻 combines 骨 (bone) with 夸, which likely contributes a phonetic element. The exact historical development is uncertain.
The left side 骨 suggests bone, and the right side 夸 looks like a person with a big stride. Picture a bone structure around the hip area that allows a wide stance.
For カ, imagine a car (カ) with a wide hip-like chassis: car -> カ, and the bone structure supports the wide frame.