Learn Hardcore Russian: Не надо оправдываться; лучше сначала выслушай меня до конца. - There’s no need to make excuses; better hear me out first.

In Russian, не надо + infinitive is a very common way to tell someone not to do something. It is often a bit softer or more conversational than a plain command.

So here не надо оправдываться is not really about lack of necessity in a neutral sense; it functions more like don’t do that.

Why is it оправдываться, and what does the -ся mean?

Оправдываться is a reflexive verb. In this context it means:

to justify oneself
to make excuses
to defend oneself verbally

The -ся often gives the meaning that the action is directed back toward the subject. So:

оправдать = to justify / excuse someone or something
оправдываться = to justify oneself / make excuses

Here the speaker is telling the other person: Don’t try to explain yourself or make excuses.

Why is it оправдываться and not оправдаться?