Of a person, deity, etc.: great in, or well-endowed with, a specified attribute. Usually with of (occasionally at). Frequently used in alliteration…

Of the sun, heat, etc.: producing a strong effect; intense, extreme. Now somewhat rare.

Great or outstanding in, of (some quality). See also so much at so, adv. conj.39. Obsolete.

transferred. Of a thing: Having some characteristic quality in a very high degree; intensely forcible, bright, hot, etc.