elusive
The definition for elusive is "Hard to grasp." Used in a sentence: The words to the song are elusive, as the singer tends to mumble.
incidental
The definition for incidental is "Minor." Used in a sentence: The accountant advised Justine not to report her incidental expenses.
incumbent
The definition for incumbent is "Necessary as a duty or responsibility." Used in a sentence: It was incumbent on Jack to attend his father's retirement party.
opportune
The definition for opportune is "Suitable or convenient." Used in a sentence: Quan stepped onto the platform at the most opportune time, just as the train pulled in.
turmoil
The definition for turmoil is "Extreme confusion, agitation." Used in a sentence: The windstorm caused such turmoil in the lake that the sailboat capsized.