na-adjective, noun
unrefined; tasteless; inelegant; prosaic; unpoetic; unromantic; boorish
Describes a person, behavior, or thing lacking refinement, elegance, or poetic sensibility. Often used in contrast with 風流 (elegance/refinement).
彼の無風流な振る舞いに、周囲はあきれていた。
Everyone was appalled by his boorish behavior.
この部屋の飾り付けは無風流で、風情がない。
The decoration of this room is tasteless and lacks charm.
風流 means elegance, refinement, or poetic taste; 無風流 is its direct opposite, meaning the lack of such qualities.
野暮 also means boorish or unrefined, but is more colloquial and often implies a lack of sophistication in social situations, while 無風流 is more literary and focuses on aesthetic or poetic insensitivity.
Compound of 無 (without) + 風流 (elegance, refinement). The alternate form 不風流 uses 不 (not) with the same meaning. The exact historical derivation is uncertain, but the word follows a common pattern of negating a positive quality.