Bona Fide

"Good Faith"

Most frequently used in contract and real estate law 

to indicate something was made or done in good faith

EX:  Sharon was a bona fide purchaser for the value of the real estate, and therefore is entitled to the protection of the recording laws.

Causa Mortis

"In contemplation of Death"

An action was taken, and the reason that it happened was in contemplation of death.  The act occurred in expectation of impending death.  The term is most commonly applied to estate planning and real estate transfers that occur because someone fears death is imminent.

EX:  The doctor told Sam he had less than six months to live.  To avoid taxes and probate, Sam was advised to transfer all his assets to his heirs.  These transfers were made "causa mortis."

Contra

"Against"

Something is the opposite of, or against, what is stated.  Besides its normal legal usage, doctors frequently use this word.  

...medicine is "contraindicated," meaning it is not advisable (indicated).

EX:  The opponent's position is contra to all known laws on the subject and will not prevail.

Corpus

"The body"

Corpus is used to indicate the body or principal amount of something. 

The verb was at one point frequently used in conjunction with other terms.

Mostly used today for the criminal term corpus delicti, meaning "the body of the crime."

Also used to signify the principal amount of a trust of the amount of a gift made by a will.

EX:  The corpus of the trust is $3,000.

Ex Officio

"By Virtue of the Office"

Someone is given a position or office merely because of his or her title.

EX:  Many presidents are ex officio members of all committees within the organization.  They are given the position as committee members because of their position as president.