From Longman Dictionary of Contemporary Englishyoofyoof1 /juːf/ adjective [only before noun] British English  relating to or intended for young people – used humorously a yoof magazineyoofyoof2 noun [uncountable] British English  young people, considered as a group – used humorously British white yoof
                                                    
                                                Examples from the Corpus
yoof• Slash'n'sideburn pop is what you get when Manc yoof grows up angry and facially bristling.• I looked for the name of yoof goddess Janet Street-Porter on the credits.Origin yoof1 (1900-2000) youth 
