define "new"... define "like"

shall we arbitrarily say that coined in the 20th century qualifies as new? (which would mean that words like 'verbicide' and 'frumious' and 'vorpal' and 'illth' are not new!) anyway, here are some:

grok (Heinlein '61)
booboisie (Mencken '22)
bibliobibuli (Mencken ??)
grotty (Burke '64)
pataphysics (Jarry '45)
pataphysical (?Lennon & McCarney '71)
senior moment (c. '98)
boondocks (?U.S. Marines '44)
backslash (BYTE '82)
garbology (Rathje c. '76)
logophile (??)

I hasten to add that I don't particularly *like 'senior moment'; it's just that I'm of an age where the phrase has a certain... je ne sais quoi.