to reach an agreement in which everyone involved accepts less that what they wanted at first:
She admitted that she was unable to compromise.
His work-mates demanded that he never compromise with the bosses.
The new regime was prepared to compromise on the oil dispute.
to do something which is against your principles and which therefore seems dishonest or shameful
compromise your principles/standards/integrity etc
As soon as you compromise your principles you are lost.
She had already compromised herself by accepting his invitation.