Something conditional is dependent on other factors. You might receive a conditional offer of acceptance from a college, depending on your high school graduation and your maintaining passing grades.
For a clue to the meaning of conditional, look at an opposing term: unconditional surrender, which means someone surrenders and doesn't ask for anything in return. In a conditional surrender, someone will give up only if certain things happen. A conditional agreement is dependent on other factors: a company could make a conditional hire, meaning they'll hire you only if you finish your degree and take a blood test. When you see the word conditional, think "It depends."
adj imposing or depending on or containing a condition
contrary to fact, counterfactual
going counter to the facts (usually as a hypothesis)
contingent, contingent on, contingent upon, dependant on, dependant upon, dependent on, dependent upon, depending on
determined by conditions or circumstances that follow
dependant, dependent, qualified
contingent on something else
probationary, provisional, provisionary, tentative
under terms not final or fully worked out or agreed upon
subject to a proviso
limited or restricted; not absolute