Did you know?

Click any word in a definition or example to find the entry for that word

old boy - definition and synonyms


What are red words?

90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.



The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.

noun [countable] British old boy pronunciation in British English
Word Forms
singularold boy
pluralold boys
  1. 2
    informal old-fashioned used by some older men for talking in a friendly way to another man

    What do you think, old boy?


sea lion

in an online conversation, repeatedly asking a person questions which suggest that you are interested in what they are talking about, but are actually intended to annoy them

BuzzWord Article

Word of the Day


to teach someone

Open Dictionary


an electric skateboard

add a word


A must for anyone with an interest in the changing face of language. The Macmillan Dictionary blog explores English as it is spoken around the world today.

global English and language change from our blog
Macmillan learn live love play