Old duffer is a colloquial term that is often used to describe an elderly person who is seen as past their prime or outdated. However, there are various other synonyms for this phrase that can be used to describe an old person without being offensive. These include senior citizen, elderly person, veteran, golden ager, old timer, aged individual, and seasoned citizen. While each of these terms has its connotations, they are certainly preferable to the derogatory term "old duffer." Hence, it is essential to be respectful and conscious of the language we use when referring to people of all ages and backgrounds.