How do you differentiate saying vague words in Japanese that have multiple meanings? E.g. tokei, koshi


I'm not talking about homonyms that have very different meanings to be able to
make it abundantly clear from context alone like hana (nose, flower) or kami
(hair, god, paper), but like tokei(watch, clock) and koshi (back and waist).

Do people just say 手の時計 for watch or 普通の時計 for a standard clock? What about
koshi? Usually people will use it in body-related topics where context alone
seems rather unhelpful because both are plausible. What then?




They are not "vague" from the Japanese standpoint. Seen from the opposite
side, I must say English is equally confusing. How do you distinguish 胃 and 腹
when they are both "stomach" in English? How do you distinguish 恋 and 愛 when
both are "love" in English? How about 兄/弟 ("brother"), 胡椒/唐辛子 ("pepper"),
ごはん/米/稲 ("rice"), 水/湯 ("water"), 絵/写真 ("picture"), 便所/風呂 ("bathroom"), and so
on?

The Japanese language makes no distinction between "watch" and "clock" at a
single-word level. Just as English speakers do not think "water" has two
meanings, Japanese speakers do not think 時計 has two meanings. 普通の時計 is either
"ordinary clock" or "ordinary watch". There are compounds like 腕時計 ("watch"),
置時計 ("table clock") and 壁掛け時計 ("wall clock") if you really need to distinguish
the types of 時計, but you should not use them without a reason.

As for 腰, it refers to the lower back and the pelvic part of the body (see the
picture [here](http://nakayama-seikei.com/archives/111)), so it's an
equivalent of neither "waist" nor "back". We also have words like 背中, ウエスト and
お尻. See also: [How can I differentiate between feet and
legs?](https://japanese.stackexchange.com/q/524/5010)

