earnest1 /ˈəːnɪst 
/ ▸ adjective resulting from or showing sincere and intense conviction: an earnest student
two girls were in earnest conversation.
– PHRASES in earnest /ˌɪn ˈəːnɪst /
to a greater extent or more intensely than before: work began again in earnest.
▪ (of a person) sincere and serious in intention: Cameron looked at him to make sure he was in earnest.
– ORIGIN Old English eornoste (adjective), eornost (noun), of Germanic origin; related to German Ernst (noun).
EnglishOxford Dictionary of English
