Abhor: A person ‘abhors’ when he/she demonstrates deep hatred for anything.
She abhors arguments!

Condone: Some people have a forgiving nature. They forgive instantly and keep moving ahead. To condone is to overlook, to ignore, to forgive, and to pardon.
Mothers are condoning in nature.

Commiserate: A person ‘commiserates’, when he/she has sympathy over the misfortunes and losses of others. To commiserate is to sympathize.

Covet: It is a word that shows a person’s irrational craving or desire for anything. To covet is to desire wrongfully, inordinately.
Example: To covet someone’s property is to desire wrongfully someone’s property.

Expiate: A villain eventually repents for what he has done and spends the later part of the life trying to amend for the mistakes he committed.
To expiate is to atone for, amend for one’s crimes.

Gormandize: A person is said to ‘gormandize’ when he/she has an unusual appetite. When he/she displays craving for eating and usually lose control while doing so.

Grovel: People who grovel literally beg and cringe at the feet of others. They have a kind of slavish attitude. To grovel is to beg, to plead.

Importune: These are the people that pester, trouble, annoy others. They have repeated demands. To importune is to pester, to annoy.

Languish: A person ‘languishes’ i.e., becomes weak when he/she hopelessly yearns/longs for something. To languish is to yearn for, long for and pine for.

Malinger: Malinger is a verb that shows the behavior of a person towards work. To malinger is to shirk, avoid work. Usually kids feign illness to escape from the school.

PS: I will keep adding more such tough words in this thread, if you happen to come across such words please share them here.