My kids are very strong minded and tend to learn experientially - which for them can mean forming theories and testing them. Seen from one perspective, that makes them "defiant" - they're not the sort of people who do what they're told, unless it's convenient for them. That's not a result of unschooling, although the fact that my stepson is that way led us to unschooling. Life got so much easier and sweeter the more we became open to the idea of helping him explore the world in ways that worked for him rather than "helpfully" telling him the "best" way - he didn't want our answers, he wanted his process.
And my daughter is similar - as a toddler she never asked what or how or why, she said "because..." and explained the world to us. She wasn't always right, but you couldn't convince her of that. It was so much better to let her have her certainty - amazingly, she didn't mind having the world prove her wrong. She just didn't want to be told. Like she didn't want the spoilers.
She also has some sensory issues - which I've discovered a lot of parents read as defiance, so it's worth mentioning in case it's an issue for your kid. A lot of the time when kids are "refusing to act right" or "making a scene" or "trying to get attention" they're really reacting to overwhelming sensory stimuli - whether that's a misplace seam in a garment, or the texture of a food, or the acoustics of a room, or any of a thousand other things. And no-one responds well when they're overwhelmed Happily, it's possible to help kids to deal with the world without being overwhelmed by it, but it's a process that actually starts by helping them find ways to minimize or even avoid the too-intense stimuli in the first place, so they can learn to deal with the world at their own, unique pace.