unfrivolous en · ADJ
Etymology
From un- + frivolous.
Meanings
-
(not-comparable) Not frivolous
The annual Americana fest is meant to help collectors […] pore through unfrivolous, astringent, functional American design.
2009 January 23, Eve M. Kahn, “Conversation-Piece Buys, Maybe. Intriguing Histories, Definitely.”, in New York Times: