Definition of as keen as mustard in English:

(as) keen as mustard

  • British informal Extremely eager or enthusiastic.
    More example sentences
    • He was keen as mustard to go and help, but we have been missing him and he's been missing us.
    • Being keen as mustard, we decided to walk from the station to the hotel.
    • Smith is just 21 and an emerging talent; bright-eyed, bushy-tailed, keen as mustard.
See parent entry: keen

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Pronunciation: kəːf
noun
a slit made by cutting with a saw