1.
prime of life; vigorous middle age
The period of life when a person is at peak physical and mental vigor, roughly corresponding to the 30s through 50s. Carries a positive connotation of strength and maturity.
壮年の男性。
A man in his prime.
壮年期に入ってから体力の大切さを感じる。
After entering middle age, you come to appreciate the importance of physical fitness.
彼は壮年にして会社を一つの大企業に育て上げた。
In the prime of his life, he built the company into a large corporation.
Compound of 壮 (vigorous, robust) and 年 (year, age). Unlike 中年 (middle age), which can carry a neutral or slightly negative connotation, 壮年 emphasizes vigor and capability.
AGE STAGES IN JAPANESE:
- 青年 — youth; young adult (roughly teens to 20s)
- 壮年 — prime of life (roughly 30s to 50s)
- 中年 — middle age (roughly 40s to 50s; overlaps with 壮年 but less positive)
- 老年 — old age (roughly 60s and beyond)
COMMON COLLOCATIONS:
- 壮年期 — the prime of life (as a life stage)
- 壮年の男性 — a man in his prime
- 壮年にして — in one's prime
REGISTER:
Somewhat formal and literary. In everyday speech, 中年 or specific age references are more common.