Amplify upon (6)
I believe the answer is:
expand
(Other definitions for expand that I've seen before include "balloon" , "increasingly elaborate" , "Mushroom" , "Extend in one or more directions" , "Distend" .)
I believe the answer is:
expand
(Other definitions for expand that I've seen before include "balloon" , "increasingly elaborate" , "Mushroom" , "Extend in one or more directions" , "Distend" .)