齢 (Kanji for stage of life)

Onyomi

REI

In Logan's Run, once people reached a late stage of life, guards were commanded to take a RAYgun and blast 'em right in the teeth.

年齢(ねんれい)	years old ★★☆☆☆ 年 (year) + 齢 (stage of life) = 年齢 (years old)
高齢者(こうれいしゃ)	old person ☆☆☆☆☆ 高 (tall) + 齢 (stage of life) + 者 (professional) = 高齢者 (old person )
適齢期(てきれいき)	a marriageable age ☆☆☆☆☆ 適 (suitable) + 齢 (stage of life) + 期 (period of time) = 適齢期 (a marriageable age)

	Meaning	Hint	Radical
噛	chew, bite	MOUTH	口
齢	stage of life	ORDER	令

Chew with your MOUTH open, but

I ORDER you to leave my age unspoken ；I'm old and it's rude to tell people.