Used to emphasize that something is nothing more than what is stated; often carries a nuance of 'just' or 'no more than'. Common in negative contexts or when downplaying something.
That is merely a rumor.
He was simply surprised.
単に also means 'merely' or 'simply', but is more formal and often used in written language or logical arguments.
Rare kanji spelling; the character 唯 is more commonly read ゆい or used in compounds.
Very rare kanji spelling; 啻 is not a jōyō kanji and is seldom used.
Rare kanji spelling; 只 is more commonly seen in the word ただ (free of charge).
Derived from the noun/adverb ただ (only, just) with the adverbial particle に. The kanji forms are ateji and rarely used.