What is another word for young and old?
Pronunciation: [jˈʌŋ and ˈə͡ʊld] (IPA) 
The words "young and old" have a variety of synonyms that can be used to add variety to your writing. For example, "youthful" is a synonym for "young" and conveys a sense of freshness and energy. "Elderly" or "senior" are synonyms for "old" and suggest a level of experience and wisdom. Other options for "young" could include "juvenile," "adolescent," or "inexperienced." Similarly, "aged," "mature," or "veteran" could be used instead of "old." Using synonyms for "young and old" can add nuance and depth to your writing and help avoid repetition.
