on a first-name basis
Quite familiar and friendly, as in Practically all the guests were on a first-name basis. This idiom alludes to the fact that using a person's given name betokens familiarity. [Second half of 1900s]
|a chattering or flighty, light-headed person.|
|a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison.|
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