How naked does a Battlebabe need to be to use Impossible Reflexes?

Exactly what it says on the tin. Just wondering how this is generally used, thanks!

This sounds like the perfect time to Disclaim Decision Making. Ask the player, work with them to figure out how naked they want to be. 

With the caveat that I've actually never been in a situation where a Battlebabe tried to use the naked option, I'd say: Naked enough that you wouldn't consider him/her even partially dressed anymore. How naked that is, probably depends upon the setting, group and maybe even situation. For some groups a bikini might work. For some underwear might be nearly naked. And in some settings/situations, only entirely naked will do.

If a player builds his or her Battlebabe on running around nearly naked, that is probably also going to be an influence, leaning towards the more dressed, bikini, part of the spectrum. But in other games it might only come up if the Battlebabe gets caught in the bath or the bedroom, entirely or almost entirely naked.

Eh, it specifies 'nearly naked' as an option, so I'd imagine even the most restrictive MC would allow skimpy enough underwear/bikini.

Really, it's pretty clearly a conceptual limitation, basically the inverse of the limitation of normal, worn, Armor 2 armor. When you're wearing Armor 2 armor, people react to you differently...you're wearing armor, after all. When you're using Impossible Reflexes for Armor 2, people react to you differently...you're nearly naked, after all.

In both cases, the primary point seems to be that, in order to benefit from Armor 2, you need to be dressed oddly for day to day interactions, rather than in something that's within the normal range of what people wear most of the time. Either way, you can describe it however you like (within reason), the primary issue is that you'll get funny looks walking around like that. At least, you will most places.

Some examples from my games include: stripped to the waist (male) and tight leather jeans, circuit board bikini, and of course naked.

Its been handled a number of ways in my game, but essentially conceptually... we used anything that someone might describe as overtly skimpy, as nearly naked enough for this move. Specifically... wearing little enough to turn everyone's head or to draw everyone's eyes counted for us. The point being, that 2-armor draws attention.

Some examples have been:

Cold World:
nearly naked: walking out of a river,  and wrapping up in only a fur cloak despite the cold.
nearly naked: wearing most of what would be normal clothing, tied up and close-fitting in a sexual way despite the cold.

Hot World:
nearly naked: showing more skin then not, probably jewels for clothing or maybe sheer silks.

Urban World:
nearly naked: a stripper's strip tease getup, before the stripping.
nearly naked: stepping out of the shower, wearing fog and towels.
nearly naked: wearing only a massive sweater, t-shirt, or button-up polo.

extended:

In the right setting, with the right people, anything could count for this really.
A good example might be battle babes from popular fiction: Skin-tight latex/leathers (matrix, kill bill, underworld)
The outfit said "sex" even if it wasn't necessarily 'nearly naked'. That's good enough for me.