Many retirees: Abbr

• Univ. applicants, typically
• Coll. short-timers
• G.R.E. takers, generally: Abbr
• Sophomores, two years later: Abbr
• Twelfth-graders: abbr
• The elderly, for short
• Matching ring recipients: Abbr.
• Some varsity members: Abbr
• Students with 300 and 400 classes: Abbr

Wiktionary Word definitions in Wiktionary
abbr. (context texting chatting English) (abbreviation of serious English)