Meagrely is the adverb from meagre. It tells you how something is done or how something is given: in a too-small way, much less than is needed. A family may be meagrely fed. A worker may be meagrely paid. A story may be meagrely told, with almost no detail. The feeling is the same as the adjective — not “a bit,” but “not enough, and it shows.” It is fairly formal. In everyday talk many people would just say “very little” or “hardly at all.” American spelling is meagerly.