ただ・只・唯・徒・但・常tada[1]atamadaka (head-high)

JLPT N3approx.Common

Which spelling to use

只只 is the most common of the kanji spellings listed here, but this word is usually written in kana alone. For beginners, 只 is the recommended kanji form.

唯唯 is a less common kanji variant than 只. It is a written form you may encounter, but it is not the preferred choice for beginners.

徒徒 is less common than 只 and 唯 as a kanji spelling of this word. It is a written variant rather than the recommended form for beginners.

但但 is less common than 只, 唯, and 徒 as a kanji spelling of this word. Beginners should use 只 instead when choosing a kanji form.

常常 is the least common of the kanji spellings listed here. It is a written variant, while 只 is the recommended choice for beginners.

Definitions

no-adjectiveordinary; common; usual
私はただの名無ななしの権兵衛ごんべえです。↗
I am just a nobody.
no-adjectivefree of chargeonly 只
私はその切符きっぷをただで手てにいれた。↗
I got the ticket for nothing.
no-adjectiveunaffected; as is; safeusu. as ただでは...
彼かれは結構けっこうしぶといね。転ころんでもただでは起おきぬ、いい根性こんじょうしているよ。↗
He's a tenacious guy who always manages to come out on top. He's the kind of guy who can turn any situation to his advantage.
adverbonly; merely; just; simply
君きみはただ皿さらを洗あらいさえすればいい。↗
All you have to do is wash the dishes.
conjunctionbut; however; neverthelessesp. 但
ただ、面白おもしろいブログを書かくために、人ひとのブログを読よむのなら今日きょうから出来できる。↗
However, if you're going to read people's blogs in order to write an interesting blog, you can do that right away.

Japanese definitions

（ただ）無料むりょう。ロハ。
（ただ）その他たのことに関かかわらず。

English equivalents

usual common ordinary

Say it right, write it right