noisome cryptics

I was working my way through edition 121 of The Puzzle People's Cryptic Crosswords magazine. In puzzle number 60 one of the clues was:

'Small number is nothing to me, just offensive.' 

Hmm...

Small number could be 'no' - as in the shortened form of numero. Next, 'is'. Okay, getting there... what about 'nothing'. Well, that's usually a letter O, as used to represent 'zero'. Then 'me'.

Okay, I knew the answer would mean offensive, and I knew noisesome would fit the bill. Yet I had too many letters. But what if I took it exactly as the clue said: no-is-o-me.

At this stage I realised I've probably been mispronouncing noisome all my adult life. (But only in my head, when reading, because I can't recall ever actually using it in conversation.)

A look in the dictionary told me it's not noise-some, as I always thought. So, what's the etymology of this strange word I thought I knew but didn't?

According to this article in The Interpreter Magazine, I'm not alone in my confusion. (At least I did know the meaning, even if I didn't know how to spell it.)

I like the definition on this page, because it places the word noisome in its family of negatively weighted words, looking back to the earlier Latin origin:

noisome
1. Offensive, especially to the senses, as to arouse feelings of disgust or repulsion.
2. Extremely harmful or dangerous.
3. Etymology: from Middle English, noysome, "harmful, noxious", from noye, "harm, misfortune"; a shortened form of anoi, "annoyance"; from Old French anoier + -some. The meaning of "bad-smelling" was first recorded in 1577.

And I think I'll remember how to spell it now, because I'll think of it as an annoyance.