This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
勥 combines 强 (strong) and 力 (power), suggesting reinforced strength or effort. The exact historical development is uncertain.
The top 强 suggests strength, and the bottom 力 adds power. Imagine a double dose of strength, but since the meaning is unclear, just remember it as a rare character related to force.
For キョウ, think of a strong person named Kyo who uses extra force: Kyo -> キョウ, and the character looks like reinforced strength.