deny, say not
If you renege on a deal, agreement, or promise, you do not do what you promised or agreed to do.
Your abnegation of something is your giving up your rights or claim to it, even though it might not be in your best interest to do so.
A negligent person does not complete what they say they will do—they are careless or inattentive to their work.
Something negative is not good in some way or can signal a *no* about something.
When you negotiate with another person, you are trying to reach an agreement of some kind, usually when doing business or trying to solve a problem.
Differentiated vocabulary for your students is just a click away.