Answer: HEP
AnswerCrossword Clue
HEPIt was "real gone" in bygone days
HEPCool, like a cat
HEPHardly old-fashioned, in an old-fashioned way
HEPCool, old-style
HEPLike some cats
HEPAware, in slang
HEPCool, in the '50s
HEPInformed, in slang
HEPLike some "cats"
HEPStart of a military march count-off
HEPHardly squaresville
HEPCool
HEPLike someone wearing a zoot suit, say
HEP"Cool," once
HEPLike certain 1940s cats
HEPCool, once
HEPwith it, in the '40
HEPCadence call
HEPWith it; cool
HEPVariety of cat?
hepwell abreast of fashionable knowledge / the fruit of a rose
HEPWith-it
HEPOn the ball
HEPWise
HEPGroovy
HEPWith it
HEPBad word before A, B, or C, briefly
HEPLike cool cats
HEPWith it, once
HEPKnowledgeable
HEPCadence shout
HEPIn the groove
HEPNot squaresville
HEPIn the loop
HEPNot square
HEPIn the know
HEPCool, in old parlance
HEPWith it, at one time
HEPFar from square
HEPHardly nerdy