What's the difference between "umbrage", "offense" and "affront"? Is it like only the second word is now in use?
Don't forget affront, insult, indignity, or outrage, which all suggest provocation, impertinence, offense, rudeness.
I got this from Wordnik, which is a great resource for detecting subtle nuances and differences in the shades of meaning between similar words. My very recent answer to your other similar question already discusses the value of this resource, so I won't delve into it again here.
I hope you'll use that resource in the future when you want to know the "difference" between two or three similar words. Teach a man to fish, and he'll fish for a lifetime.
My curtness here is only because I don't want to repeat myself; please don't feel affronted, I don't mean any offense.
To take umbrage is to take offence - these are equivalent in meaning (see dictionary.com)
To affront is to insult someone, so it is slightly different.
Both offence and affront have a noun form, whereas umbrage is no longer used except in the "take umbrage" form.