I'm here to proclaim **musick** as the winner of this round, as he not only correctly voted but also collected the most "playing" votes. here's the evidence:

a) a feeling of emptyheadedness often experienced after saying something idiotic [tsuwm]

b) a recently coined corruption of Loch Ness, intended to be humorous, referring to the amount of folklore and mythology surrounding various tourist sites; examples of high "arghness factor" would be Loch Ness and the Blarney stone. [Zed] WO’N

c) wittiness (obs.) [Sparteye]

d) the monstrous pain of being Scottish [sjmaxq] ASp

e) a musical term for measuring the quality of a bagpipe's pitch. [WO’N]

f) a cape or head that rises in a shallow slope from relatively low land, terminating in a precipitous drop to the sea with no or only a very narrow beach region. [Faldage] ChurlPat, VernonC

g) obs. the darkest day of winter (related to Old Icelandic aarkneiss) [maverick] Jackie

h) the measurable moisture content of the organic base in a forest bed. [musick] maverick, Zed, Sparteye

i) early electrical hot water system (named after its inventor). [Bingley]

j) a land filled with satisfying targets, none of which can be harmed or will hurt you back no matter what you do to them. [Jackie]

k) dominatrix [VernonC]

l) an intensifer popular among teenagers for the groan commonly spelled argh, as in: "Ohmygod that is such total arghness!" [ASp] etaoin, maxq, Bingley

m) obs. cowardice, pusillanimity, timidity [OED] musick, Faldage

the only other comment I have is that this is another word which shows up in the Catholicon Anglicum (mentioned elsewhere, in today's wwftd is.. unthirlable). I could become enamored of this venerable incunabulum as a resource, here and there...

Arghnes, pusillanimitas

as always, thanks to all