The definition for commemorate is "To mark by a ceremony." Used in a sentence: Each year, the Franklins commemorate their anniversary by visiting the site of their first date.

The definition for comparable is "Similar, equivalent." Used in a sentence: Helen will only accept something of comparable value for her ticket to the concert.

The definition for curtail is "To make less." Used in a sentence: Doreen decided to curtail her spending after she bounced a check.

The definition for diffident is "Lacking self–confidence." Used in a sentence: The diffident student never raised her hand in class, even when she knew the answer.

The definition for mandate is "An official order or commission to do something." Used in a sentence: Martha reluctantly obeyed the mandate to vacate her apartment.