enjoin, advise, preach to
勖 centers on urging someone to do the right thing: enjoining, advising, or preaching to them with a sense of moral encouragement.
勖 combines 力 (strength, effort) with 冒 (to risk, brave), suggesting the idea of urging someone to exert effort bravely. The exact historical development is uncertain.
The left side 冒 looks like a helmet (目 over 冂) and the right side 力 is strength. Imagine a commander putting on a helmet and urging the troops forward with strong advice.
For キャク, imagine a character named Kyaku (キャク) who always preaches to others. Kyaku -> キャク, and his strong words enjoin everyone to do better.