regrettable：令人遗憾的，可惜的，可悲的  

词根词缀：regret遗憾,懊悔 + -able形容词词尾

• fabric
• fabricant
• fabricate
• fabrication
• fabricator
• fabulist
• fabulous
• facade
• face
• facet
• facetious
• facial
• facile
• facilitate
• facility
• facing
• facsimile
• fact
• faction
• factionalism
• factionary
• factitious
• factitive
• factoid
• factor