The phrase "fashion radar" refers to someone's ability to notice and keep track of fashion trends or styles. It describes how aware or attuned a person is to what is currently considered fashionable. Full definition
Oversized clothes and dresses, are on the right fashion radar this 2015. (thefashionflite.com)
I started hosting these parties when they were barely a blip on the ethical fashion radar — indeed, when ethical fashion itself wasn't yet a «thing». (bluecollarredlipstick.com)
While my feet may still be in snow, my fashion radar is in spring. (momtrends.com)