[magus]

No Clue

Cash in Nashville   JOHNNY
Second degree?   MBA
Theme:  terms denoting lack of cognition but with no clues given for those terms
PEABRAIN, DINGBAT, AIRHEAD, SPACECADET, NINCOMPOOP
Like five answers in this puzzle, literally and figuratively   CLUELESS

 
Hi-___   FIS [not wild about the –S to complete the term, which is hi-fi]

RATING: Three grins = Excellent: Loved it; Two grins = Good: Enjoyed it; One grin = Satisfactory: A bit bland for my taste; One teardrop = Unsatisfying: No fun