1. Noun which may take the genitive case particle 'no', Noun

   ordinary; common; usual

   Usually written using kana alone

   私はただの名無しの権兵衛です。

2. free of charge; free

   Usually written using kana aloneesp. 只 if written with kanji

3. unaffected; as is; safe

   Usually written using kana aloneusu. as ～では...

4. Adverb (fukushi)

   only; merely; just; simply

   Usually written using kana alone

5. Conjunction

   but; however; nevertheless; except

   Usually written using kana aloneesp. 但 if written with kanji

Also written 唯【ただ】tada、徒【ただ】tada、但【ただ】tada