An identifier (it doesn't need to vary) whose value is represented with an arbitrary length of bits has many names:
Bit string, bit vector, bit array, bitmask, bit map, bit set, ...
There is no single name that only says you will treat the value in a bitwise way. And no way to guarantee that the only way the value will be treated will be bitwise. Every one of these names intends to communicate other features as well. Sorry. We don't have your word. Bitwise is the name for how you will treat the value (as bits). It's not the name of such bits.
However, if you want to say both that you will treat the value in a bitwise way and that each bit will be interpreted as it's own Boolean value then consider bit flag. Bit fields are not limited to a Boolean interpretation.
And, as Doc Brown points out, it’d be nice if the identifier name also reflected the domain.