1. Grave, sober, solemn refer to the condition of being serious in demeanor or appearance. Grave indicates a weighty dignity, or the character, aspect, demeanor, speech, etc., of one conscious of heavy responsibilities or cares, or of threatening possibilities: The jury looked grave while studying the evidence. Sober (from its original sense of freedom from intoxication, and hence temperate, staid, sedate) has come to indicate absence of levity, gaiety, or mirth, and thus to be akin to serious and grave: as sober as a judge; a sober expression on one's face. Solemn implies an impressive seriousness and deep earnestness: The minister's voice was solemn as he announced the text.

Did you mean gravel?