I googled "what does smart casual mean" too and I don't see the term hipster on the first page at least in the brief summaries.

the first definition is: (of clothes) neat, conventional, yet relatively informal in style, especially as worn to conform to a particular dress code.
"think of a smart casual outfit as one that you'd wear for a movie or dinner date"

to me it means a step below Sunday dress- no tie needed; khakis and a collared shirt