Vocabulary and Synonyms

Sardonic is something cynical, satirical or ironic.

To goad is to provoke or annoy someone so as to stimulate some action or reaction. Urge is the closest synonym.

A reprisal is an act of retaliation. Injury in return is the definition provided.

To regale is to entertain or amuse someone with talk. Entertain is the correct synonym.

Quirk means to twist or turn one's mouth or eyebrows suddenly to express surprise or amusement.

The scientist is merely doing his job for which he is being paid.

Dexterous means to be adept or agile.

Cheerful

Goad is to annoy or stimulate an animal or person into action. Hence, spur is correct as it means the same thing.

Skinflint

To pay very high prices

A mortar is a vessel, typically made of hard stone or ceramic, used in conjunction with a pestle (the 'cudgel' mentioned) to grind or crush substances into powder.

Detour is a long or roundabout route that is taken to avoid something or to visit somewhere along the way.

This is the correct answer. A nom de plume is an alias or a pen name.

Regret means to feel sad, repentant, or disappointed over (something that one has done or failed to do).