The term 'No Longer Active' can be abbreviated in two ways: RETD (4 letters) and RET (3 letters). RETD stands for Retired, which is a term used to describe someone who has left their job or profession after reaching a certain age or length of service. RET stands for Retired from Active Duty, which is a term used to describe someone who has left the military after completing their service. Both terms indicate that the person is no longer actively working in their respective field.