Shapes are tall on the side (7)
I believe the answer is:
lateral
'on the side' is the definition.
(I've seen this before)
'shapes are tall' is the wordplay.
'shapes' indicates an anagram (shape can mean to mould or transform).
'are'+'tall'='aretall'
'aretall' with letters rearranged gives 'LATERAL'.
(Other definitions for lateral that I've seen before include "Side branch" , "belonging to the side" , "Shoot" , "Way of thinking" , "Relating to the side" .)