This is the adverb of 'stolid'. It describes HOW someone does something: with no visible feeling, no reaction, when a reaction would be expected. He stared stolidly ahead. She went on eating stolidly while everyone argued. Because it is an adverb, it usually sits with a verb of looking, sitting, standing, listening, waiting, or continuing — quiet, still actions. That is worth noticing, because you would rarely say someone 'ran stolidly'; the word wants a body that is not moving much. Like 'stolid', it leans disapproving: it suggests dullness rather than admirable self-control. But it also has a second flavour that the adjective has less of — stubborn continuing. When someone works stolidly on, or waits stolidly in the rain, you feel they are unmoved and will not stop, and there can be a quiet respect in that. It is a written, formal word; you will meet it in stories, not in a conversation at the night market.

面無表情地、木然地、無動於衷地（stolid 的副詞）。也常帶「一聲不吭地繼續做下去」的意味。