Stand-offishness is the noun: the coldness itself, the quality of keeping people at a distance. Not the person, and not the way they act — the thing they have. "I was surprised by his stand-offishness." "Her stand-offishness melted after the second cup of tea." This is what nouns like this are for. Once the quality has a name, you can do things to it in a sentence: notice it, explain it, forgive it, watch it disappear. That is why you often find this word in the middle of a kind sentence — someone is trying to account for behaviour that hurt a little. "His stand-offishness was really just shyness." It is uncountable: stand-offishness, some stand-offishness, a certain stand-offishness — but never "a stand-offishness" on its own and never plural. It is also, honestly, a rare and rather heavy word; five syllables is a lot. In speech most people say "he was so cold with me" instead. Keep it for writing, where a long word has room to sit. Both spellings work: stand-offishness and standoffishness.

冷淡、疏離（那種態度本身）。是 stand-offish 的名詞形，指「不想跟人親近的那種態度」。不可數，而且是書面語，講話時多半直接說 he was cold。