1Used with a negative to mean "not particularly" or "not especially." Also used alone in casual conversation as a reply meaning "nothing in particular."
「疲れてない?」「別に。」
"Aren't you tired?" "Not really."
別に嫌いなわけじゃないけど、あまり食べたくない。
It's not that I dislike it in particular, I just don't feel like eating it much.
その映画、別に面白くなかったよ。
That movie wasn't particularly interesting.
別に急いでいないので、ゆっくりで大丈夫です。
I'm not in any particular hurry, so take your time.
2Used to mean doing something separately or in addition, rather than together — as in "prepare separately" or "an extra charge applies."
荷物が多いので、これは別に送ります。
Since I have a lot of luggage, I'll send this one separately.
サービス料は別にいただいております。
A service charge is billed separately.
子ども用のメニューを別に用意した。
We prepared a separate menu for children.