Actually "specular" is an adjective and not a noun or verb. Spectacular is a state of being, but does not define what that state is. It could be good or bad. It;s like saying somebody is really amazing: its not necessarily a compliment.  I think Trump chose the word very carefully:  to flatter the gullible lad yet remain  non-committal. " Well will you look at that! Isn't he, you know what I mean, that's  just just so,  it  really is."