Over-hasty refers to something that is done too quickly, without enough thought or consideration. Antonyms for this word would be actions or decisions that are taken after careful consideration, without haste, or in a timely and appropriate manner. Words such as deliberate, considered, cautious, reflective and prudent can be used as antonyms for over-hasty. Additionally, words such as meticulous, circumspect, thoughtful, and judicious can all be used as antonyms to describe actions or decisions made with care and attention to detail. Essentially, the opposite of over-hasty is taking the necessary time and thought to make a wise decision, rather than rushing into something that might lead to mistakes or regret.