Dependability is a key attribute that can make or break a person's reputation. However, when someone is described as un-dependable, it means that he or she cannot be trusted or relied upon. The opposite of un-dependable would be dependable or reliable. A dependable person is someone who can be relied upon to always keep their word and do what they promised. Other antonyms for un-dependable include trustworthy, responsible, dependable, punctual, honest, and committed. An individual who possesses these qualities will always be considered dependable and will be able to earn the trust and respect of those around them.