Oops! This feckin' thing is on a hair-trigger.

As the previous contributor (whose name I was trying to check out when it went off in my hand, Sir) correctly points out, "fecking" used as an attenuation of the expletive "fucking" is not considered coarse. This is borne out by the fact that it would never be used as a substitute for the verb "fuck" in its substantive sense. My father (born Dublin 1904, just a few weeks before Bloomsday, though he wouldn't have had any time for that vulgar Joyce fella) used it in informal conversation, whereas he would NEVER use the other "four-letter word".

Apart from "to feck" as a substitute for "steal", the verb "to feck around" is also used in the sense of acting indecisively or fruitlessly (intriguingly, the corresponding French verb "pinailler" also has "coarse" origins, but seems to be acceptable in reasonably polite usage which evidently disregards its origins): e.g. "Stop fecking around and make up your mind"

There is also the slightly less common adjective "fecky" meaning either pernickety or irritatingly complicated, requiring the user to feck around with whatever is so described, e.g. an appliance with "all sorts of fecky little knobs on it", or someone at a meeting raising lots of fecky little procedural points.