|©Nancy E. Banks|
It sounds like what it means, which is to rummage. According to Webster's Third New International Dictionary, Unabridged, it comes from Australia, where it specifically means "to search for gold typically by picking over abandoned workings." Rummaging, in other words.
An added bonus is the etymology, where one learns that it's a dialect irregular form of "fuss."
So, rummaging with a side of fussing while looking for something valuable.
This is a Word I Can Use. Because it turns out that I spend a lot of time fossicking. For example: I was fossicking in the junk drawer this morning for the AA batteries that I just put in there, but I couldn't find them. Could be it's time to clean that drawer out. Or: No amount of fossicking in the "Sent Mail" folder will turn up the itinerary I was supposed to forward to my sister if I failed to actually forward it in the first place.