Is “Ruder” a Scrabble word?
Yes
RUDER
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Ruder
adjective
1.Bad-mannered.
“Karen broke up with Fred because he was often rude to her.”
2.Somewhat obscene, pornographic, offensive.
3.Tough, robust.
Synonyms: ill-mannered, uncouth, adult, blue, primitive