meritorious deed, merits, rank
勛 centers on recognized achievement: a meritorious deed that earns distinction or rank.
勛 combines 員 (member, official) and 力 (strength, effort), suggesting an official's meritorious effort leading to rank or distinction. The exact historical development is uncertain, but the component relationship is consistent with the meaning.
An official (員) puts in effort (力) and earns a meritorious deed that raises their rank.
For クン, imagine a coon (a raccoon) being awarded a medal for its meritorious deed: coon -> クン, and the raccoon's effort is recognized.