一不小心 yībùxiǎoxīn HSK7 carelessly Origin Definitions Defs Strokes Stroke Words Sentences Sents 一 yī adverbnumeral [suddenness] Used before a verb to indicate that an action or situation occurs suddenly or unexpectedly.不小心 bùxiǎoxīn adverb carelessly to do something by accident or without paying attention; inadvertently