Adhesion: the insurer writes the contract; the applicant can only take it or leave it. A genuinely ambiguous clause is therefore read in favor of the insured.

Aleatory: an unequal exchange that depends on chance. One month's premium can bring a year of disability benefits, while another insured pays for decades and never collects.

Personal: the contract is with a particular person the insurer evaluated, so that person's health, occupation and honesty matter. Calling it personal does not make the agent liable for claims, and businesses can buy insurance too.

Unilateral: only the insurer makes a legally enforceable promise. If the insured stops paying premiums, the coverage simply ends; the insured cannot be sued for the premium. A contract in which both sides promise future performance is bilateral.

Conditional: the insurer pays only if conditions are met, such as a covered loss occurring, premiums being paid and proof of loss being filed. Being conditional does not let the insurer change the terms or walk away at will.