From Dictionary.com:
I don't know if that helps or not.
my two cents is that working at a live music venue I've heard my fair share of smooth jazz, and although it's not my cup of tea and I also find it to be a fairly narrow, confining, and repetitive genre, there is PLENTY of improvisation within the groups that I have heard. It's just slowed down and more straightforward (read as "smooth") than the improvisations you hear in the more athletic and hectic jazz groups.
Jazz
noun
1.
music originating in New Orleans around the beginning of the 20th century and subsequently developing through various increasinglycomplex styles, generally marked by intricate, propulsive rhythms, polyphonic ensemble playing, improvisatory, virtuosic solos,melodic freedom, and a harmonic idiom ranging from simple diatonicism through chromaticism to atonality.
2.
a style of dance music, popular esp. in the 1920s, arranged for a large band and marked by some of the features of jazz.
noun
1.
music originating in New Orleans around the beginning of the 20th century and subsequently developing through various increasinglycomplex styles, generally marked by intricate, propulsive rhythms, polyphonic ensemble playing, improvisatory, virtuosic solos,melodic freedom, and a harmonic idiom ranging from simple diatonicism through chromaticism to atonality.
2.
a style of dance music, popular esp. in the 1920s, arranged for a large band and marked by some of the features of jazz.
I don't know if that helps or not.
my two cents is that working at a live music venue I've heard my fair share of smooth jazz, and although it's not my cup of tea and I also find it to be a fairly narrow, confining, and repetitive genre, there is PLENTY of improvisation within the groups that I have heard. It's just slowed down and more straightforward (read as "smooth") than the improvisations you hear in the more athletic and hectic jazz groups.

