I'm looking for a word that would describe someone who despite giving their best efforts, they always barely get by. Someone who tries hard but has to put in their best effort just to meet standards at their job. They manage to get the work done by the skin of their teeth when others find the same job to be easy.
This person doesn't fail, they SOMEHOW manage to meet standards. But every day is like, "All that work for a C-"
I've considered mediocre, but that seems like it describes the person's results more than it does the person.
The phrase, "coasting through life" comes to mind, but that to me implies lack of effort.
The phrase "hanging by a thread" comes to mind, as this person often feels like that is what they are always doing.
The closest thing I can think of is "fumbley" (if that was a word.) As this person is often set back by mistakes, clumsiness or in some cases just not able to think and act as fast as their peers, yet they can manage to get the work done as long as they work harder than everyone else.