The term 'STYLISH '60s Londoner' refers to a person who was fashionable and living in London during the 1960s. The crossword solution for this term is MOD, which stands for Modernism. This movement was popular in the 1960s and was characterized by a focus on modern art, fashion, and music. MODs were known for their sharp dress sense and often wore brightly colored clothing, such as suits and miniskirts. They also had a fondness for music, particularly British bands like The Who and The Kinks.