your costume is so fail!

Hello again! This is the first time I posted in such quick succession but I heard something last night during my Hall's Dance Production (DP) vetting which reminded me of an instance of how my own lexicon has changed recently. The Stage Manager was giving us feedback on our first run, and was evidently rather close to panicking due to DP being a few days away. Hence she was using the 'fail' word quite a bit, and in exasperation, had used it in a form most commonly heard nowadays, in that of a noun and an adjective. I thought nothing of it and understood it very well indeed.
E.g.)
'That costume is so fail!' (~adjective to describe the noun, 'costume'; an adjective as it can be preceded by a quantifying adverb, 'so')

'Why was your facial expression so off? You are an epic fail!' (~noun)

A search for 'fail' in the OED, Macmillan, Longman, Cambridge and Merriam-Webster did reveal that it could be used as a noun, but the phrasing of 'fail' in the dictionaries was different, with the noun mainly used in forms like Longman's:

1

without fail

a) if you do something without fail, you always do it:

Tim visits his mother every day without fail.

b) used to tell someone very firmly that they must do something:

I want that work finished by tomorrow, without fail!

2 [countable]SE an unsuccessful result in a test or examination [≠ pass]:

I got a fail in history.

Also, 'fail' was not used as an adjective in the dictionaries mentioned above. I feel that these new usages of 'fail' which I have adopted into my mental lexicon are a result of the recent websites like the Failblog.org, whereby instances of screw ups by people are posted on the blog, and labelled as a 'fail', or something to be ridiculed.