ordinary; common; usual.
彼はただの学生だ。
He is just an ordinary student.
これはただの風邪だから、あまり心配しないでください。
This is just a common cold, so don't worry too much.
ただの偶然だと思う。
I think it's merely a coincidence.
free of charge; gratis.
このコーヒーはタダです。
This coffee is free.
子供は入場料がただだ。
Children get in free.
サンプルをただで配っていた。
They were giving out samples for free.
to remain unaffected or get off without harm/penalty (often seen in phrases like 'ただで済む').
事故になったが、幸いにもただで済んだ。
There was an accident, but fortunately we got off without harm.
今回は警告ですんだが、次はただでは済まないだろう。
This time it was only a warning, but next time it probably won't be so simple.
only; merely; just; simply.
私はただ話を聞いていただけです。
I was simply listening.
彼はただ疲れているだけだ。
He's just tired.
ただ勉強しているだけでは合格できない。
Just studying isn't enough to pass.
それはただの噂に過ぎない。
That's merely a rumor.
but; however; nevertheless (used as a conjunction, often in the form 'ただ, ...').
行きたい。ただ、時間がないんだ。
I want to go. However, I don't have the time.
彼の意見は面白い。ただ、実現は難しいと思う。
His idea is interesting, but I think it's hard to put into practice.
天気はいい。ただ風が強い。
The weather is fine. However, the wind is strong.