difficult progress
軻 centers on the idea of difficult, obstructed progress, like a cart that cannot move smoothly.
軻 combines 車 (cart, vehicle) with 可, which likely contributes the sound. The character suggests a cart that encounters difficulty, fitting the meaning of difficult progress.
A cart 車 beside the component 可, which here can be thought of as a roadblock. Imagine a cart trying to move forward but hitting an obstacle, making progress difficult.
For カ, picture a car stuck in mud, unable to move: car -> カ, and the cart's difficult progress matches the kanji meaning.
—