mister, you, ruler, male name suffix
君 centers on a person of respect or address: a ruler, a formal 'you,' or a polite suffix for male names. The core idea is a figure with some authority or familiarity.
君 combines 尹 (a hand holding a staff, suggesting authority) with 口 (mouth, here indicating command or speech). Together they represent a ruler or lord who issues commands.
The top part 尹 looks like a hand holding a staff of authority, and the bottom 口 is a mouth giving orders. Picture a ruler speaking commands: 君 is the person in charge.
For クン, imagine a ruler named Kun giving orders: Kun -> クン, and his mouth 口 speaks with authority.
Mr; master; boy
you; buddy; pal
you (people)
you (plural); all of you; you all
monarch; sovereign; ruler; liege (lord)
reigning (over a country)
Imperial reign
lord; master
tyrant; despot
daughter of a person of high rank (esp. eldest daughter)
man of virtue; wise man; (true) gentleman
you (primarily used by men in letters to their equals or inferiors)
sovereign; ruler
wise ruler; enlightened monarch; benevolent lord
(one's) wife
emperor
monarch
young lord or prince
(another's) husband
father