Accept ↔ Refuse
Accept
To say yes to something offered.
Ananya was happy to accept the invitation.
Refuse
To say no to something offered or asked.
Vikram refused the extra sweet; he was full.
Reject
To refuse firmly; to turn something down as not good enough.
The shop rejected the damaged parcel.
Remember: Refuse is the everyday word for saying no. Reject is stronger and often means 'not good enough': refuse a second helping, reject a faulty product.