The word "un-fit" is an adjective that denotes something that is not suitable, appropriate, or qualified for a particular purpose. Its antonyms are well-fit, suitable, appropriate, qualified, and capable. Well-fit means being in good health, strong, and physically capable of performing a task or activity. Suitable refers to something that is appropriate, ideal, or appropriate for a particular purpose. Appropriate implies that something is satisfactory, proper, or fitting for a given situation. Qualified signifies that someone is fully trained, experienced, or competent to perform a job or task. Capable suggests that someone has the skill, knowledge, or ability to complete a task successfully.