In medicine, nonspecific means not assignable to a particular cause, condition, or category.
FLAIR is an MRI sequence which stands for fluid attenuation inversion recovery, typically included in protocols for brain imaging, particularly useful in the detection of subtle changes at the periphery of the hemispheres and in the periventricular region. By doing so, potential abnormalities are highlighted and made bright but normal cerebrospinal fluid is attenuated and made dark.