Meanings of plead extenuating in English

I admit the fact freely, but beg to be permitted to plead extenuating circumstances.

Still it is rather late to plead extenuating circumstances.

I could no longer plead extenuating circumstances: I could not bemean myself by trying to explain-

I should plead extenuating circumstances, dearest.

Don't plead extenuating circumstances.

An artillery that, after the third shot, found the proper curve and bent the cross on the cathedral, cannot plead extenuating circumstances and stray shots.

You did not absolutely confess the existence of your mistresses, but you pleaded extenuating circumstances.

Mr. Eddy and others pleaded extenuating circumstances and proposed that the accused should leave the camp.

Was not he, too, pleading extenuating circumstances?

Before the inquiry progressed, the attorney for the plaintiff apologized to the court, pleading extenuating circumstances in the offense offered to his client.