珍 vs 珍しい (na-adjective and i-adjective)

Question

珍 is a noun but also a na-adjective while 珍しい is an i-adjective. In terms of usage, is there some rule of when we should use one and not the other? For words that have a i-adjective and a na-adjective form is there any general usage rule?

Answer 1

「珍{ちん}」 and 「珍{めずら}しい」 are two fairly different words in terms of usage.

「珍しい」 ("rare", "uncommon", etc.) would be much easier for Japanese-learners to use as it can precede and modify almost any type of noun -- wago (originally Japanese word), Sino-loanword and non-Sino-loanword.

When you find something to be rare, uncommon, etc., you can describe it as 「珍しい + Noun」. It is that simple.

Note that 'mezurashii' is a 100% originally Japanese word. Don't let the kanji 「珍」 fool you as that was only adopted later.

「珍{ちん}」, however, is quite different in its usage if not in meaning. You cannot just say 「珍 + any noun」 every time you find something to be rare.

「珍」 is most often used like a prefix that precedes an on'yomi noun as in:

・「珍客{ちんきゃく}」 = "rare guest"

・「珍菓{ちんか}」 = "rare confection"

「珍」 can precede non-Sino-loanwords as in:

・「珍プレー」 = "sports bloopers"

・「珍メニュー」 = "rare or strange dish" (メニュー does not mean "menu" here.)

I, however, could not think of a common term that takes the form of 「珍 + wago noun」. On-kun combinations are
rare to begin with.