Achromatic

adjective

1. Free from color; transmitting light without color-related distortion.
2. Containing components such as achromatic lenses and prisms, designed to prevent color-related distortion.
3. Uncolored; not absorbing color from a fluid; -- said of tissue
4. Having only the diatonic notes of the scale; not modified by accidentals.
5. Being achromatic in subject

   "The lecture was achromatic, the speaker used politics to suppress the weight of his/her subject."