There’s nothing like age to make you humble. I’m turning a nice, round number later this year — let’s just say I’m アラフォー (arafō, around 40) and leave it at that — and perhaps because of that, the phrase いい歳 (ii toshi) has been rattling around in my mind.

If you take いい歳 too literally, you end up with an English term like “good age.” But a more accurate translation would be “decent age” or “sensible age,” at least in a vacuum without any context.

However, language is insidious. While I was sitting here chuckling at myself for getting “pretty old,” I didn’t realize until I looked into the phrase further that it can actually have quite detrimental effects on people, depending on how it’s used.

In the dictionary, いい歳 has two definitions. The first is relatively harmless: 相当な年輩。 「先生も、もう好い年だろう」 (Sōtōna nenpai. “Sensei mo, mō ii toshi darō,” Considerably old. “Sensei, you’re starting to get pretty old yourself”).

This is the meaning I initially had in mind.

At this point, it’s also worthwhile to note that いい歳 can be written with any combination of 良い, 好い and いい for ii (good/suitable) and 歳 (toshi, year of age) or 年 (toshi, calendar year/year of age) for toshi. The most frequent combinations are いい年 and いい歳, despite the dictionary listing.

The second definition is the one that can cause trouble: 十分に分別のある年齢。多く、年齢に不相当な行為などをあざける気持ちを含んで使う。「好い年をしてばかなまねをするな」 (Jūbun ni funbetsu no aru nenrei. Ōku, nenrei ni fusōtōna kōi nado o azakeru kimochi o fukunde tsukau. “Ii toshi o shite baka na mane o suru na,” An age with sufficient good judgment. Often used in a manner to scold someone’s actions as inappropriate for their age. “Act your age and quit being such an idiot”).

Obviously, the use of ばか (baka, idiot/idiotic) is not recommended in polite company, but the more subtly damaging phrase here is 好い年をして (ii toshi o shite, act your age/grow up), which can be found more casually and frequently as いい歳して (ii toshi shite).

This leads to the question: What age should we be acting, exactly?

The Japanese internet is torn on exactly how old one needs to be to qualify as いい歳. One commenter on the Oshiete Goo website notes 若いは18歳まで、いい年は40歳から (wakai wa 18-sai made, ii toshi wa 40-sai kara, you’re young until 18, and you’re ii toshi from 40).

On Yahoo Chiebukuro, a commenter pinpoints いい歳 as exactly 27 years old: 27歳くらいからかな?自分がその位から「いい歳なんだからちゃんとしなきゃ」と思い始めたので (Nijūnana-sai kurai ka na? Jibun ga sono kurai kara “Ii toshi nanda kara chanto shinakya” to omoihajimeta no de, Maybe around 27? Because that’s around the point when I started thinking, “I’m ii toshi, so I need to do things properly”).

Another commenter notes that いい歳 is entirely subjective: 言う人の年齢により違うと思います (Iu hito no nenrei ni yori chigau to omoimasu, I think it depends on the age of the person saying [“act your age”]). Their age will inevitably influence what they perceive as appropriate or inappropriate for other ages.

The subjectivity is where the phrase can be dangerous. Who determines the appropriate age to get married? To stop playing video games? To move out of your parents’ house? To stop watching professional wrestling? To stop dying your hair? いい歳して relies on subjective personal and societal biases that disproportionately affect women and the young.

This is reinforced by an article on Mynavi Woman by advice columnist Yusuke Asada titled “「いい歳して」っていくつのこと?もし言われた時の8つの対応法” (“Ii toshi shite”-tte ikutsu no koto? Moshi iwareta toki no yattsu no taiōhō, How old is “Acting your age”? Eight ways to respond when someone tells you to “act your age”).

The article outlines a number of reasons someone might tell you to いい歳して, including being unemployed, living with parents, chasing your dreams, being single, enjoying “childish” things or not being “polite enough.”

So how should one respond? First, the article recommends not letting the person get your goat, so to speak: まず落ち着きましょう (Mazu ochitsukimashō, First, calm down). Then, make an effort to set appropriate boundaries: 相手の価値観を無理して受け入れる必要はありません (Aite no kachikan o muri shite ukeireru hitsuyō wa arimasen, You don’t have to force yourself to accept someone else’s values).

Asada recommends a balanced approach: consider where the person is coming from and whether they have a point, try explaining to them how you live your life/your goals and if you realize they have different values from you, 距離を置く (kyori o oku, put some distance [between them and yourself]).

We also have to be careful not to tell ourselves to いい歳して. Sometimes we unknowingly place limits on our own actions because of what we believe others think is appropriate. In reality, these are often artificial and subjective.

Ideally, as we grow older we should only become more comfortable in our own skin and more certain that even if someone tells us to “act our age” that we’re already doing it and they are the one in need of an attitude adjustment.

いい歳 has been an eye-opening phrase for me. It has made me think harder about the effects words can have, and I’m now more determined to use both English and Japanese with care and to approach life and language with curiosity, rather than judgement.

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