べつbetsuni
1.

An expression used to indicate that there is nothing of particular importance or urgency to mention, often in response to inquiries or suggestions.

2.

A way to convey a sense of indifference or lack of concern regarding a situation or topic, implying that the speaker does not feel the need to emphasize or engage with it.

3.

A response that suggests the speaker neither has any specific desires nor is affected by the matter being discussed, often used to lightly dismiss questions or offers.

Example:

たまにまる一日ぼけっとしていても別に悪い事じゃない。

とはtohaべつbetsuni
1.

Something that exists or occurs aside from the main topic or matter being discussed, highlighting an additional or separate aspect.

2.

Referring to an alternative or distinct element that is not included in the primary consideration, often used to introduce a supplementary detail or exception.