A person who is aspiring and basing their entire lives off being a femboy. An aspiring femboy is not a full fledged femboy yet, rather a femboy in training. They will most likely take the "Belle Delphine approach" and start up a freebase website to sell their own bathwater to discord and Reddit mods.
O:"Hey, have I ever told you that I'm an aspiring femboy?"
A:"If you start selling your bathwater on eBay I'm never speaking to you again"