Faddishness is the quality of running after a fad: a look, a diet, a gadget, a way of talking that everyone suddenly loves, then quietly drops. The thing itself is the fad; faddishness is the habit, or the air, of that short, hot liking. When we talk about the faddishness of a decade, we mean how quickly its passions turned over. The word is a little cool and a little judging — it suggests the love was never deep. You will see it more in essays and reviews than in the kitchen. A speaker who wants the same idea in easy talk will just say someone is following a fad, or that something is only a trend. Though actually, a fashion can last and still be a fashion; faddishness is the kind that does not last, and does not mind.