U字開頭的單詞或詞組
UMBunceasinguninhabitableunmaskup one's streetusual practiceunder footunit numberunpickunfeasibleunstructuredundockup-and-downuracilultrasonographyunburdenUnion of Soviet Socialist Republicsuntrustworthyundetecteduniversal machineunderwriteuncloudeduveitisUMAundercoatundercurrentup onunobtrusiveupholsteryupliftedunattractiveunmatchableunderwooduglilyunfaithfulU.S.A.unadjustedunsetunimpressedunderwritingupdate informationundivided