Discuss and learn French: French vocabulary, French grammar, French culture etc.
i meant to say "desperately"
I don't think you have to use the "desperate" connotation (it could involve desperation)
Maybe "strong or fierce resolve" might give a better sense (just my feeling).
I have come across it although I doubt if it is particularly common.
A nice verb though.
i like "un sportif acharne'" which is a "sports freak" and so by extension i could use it to describe others where an adjective defines the person (and maybe it doesn't have to b an adjective).