The term 'not as common' can be summarized by two crossword solutions: 'SCARCER' (7 letters) and 'rarer' (5 letters). Both words refer to something that is not as common or abundant as other things. SCARCER is a more formal word than rarer, and it is often used to describe something that is in short supply or hard to find. Rarer is also used to describe something that is not as common, but it is less formal than SCARCER.