Speaking of Mavourning, Grandma (Genevieve) Wright frequently used the word "malfooster." The most common usage was, "Stop malfoostering that child!" My parents always wondered where she got the word but could not find it in any dictionary. In college, when I was reading Ulysses I came across the word "foos" and a footnote said it was probably a reference to "fooster," which is Irish for fussing, dawdling, or wasting time. We guessed she added the mal- prefix just to make it negative.
But the construction wasn't hers. I recently searched for malfooster on google and found this entry in Cassell's Dictionary of Word and Phrase Origins :
Banjaxed, to be. An Irishism meaning 'banged about; smashed' and introduced into popular British speech by the broadcaster Terry Wogan in the early 1970s. Possibly from Dublin slang of the 1920's. When he wrote a book called Banjaxed(1979), Wogan supplied this definition of the verb: To hornswoggle, corpse, knacker, rasher, caramelize, malfooster, malavogue,powfagg, keelhaul, macerate, decimate, pulverize, make rawmeish of...
And I also found this definition at www.hiberno-english.com under an alternate spelling:
// v. to give a beating (to someone) < F mal + Ir. fústar. 'If you don't stop that messing I'll mallafoosther the both of you'.