Why do we use the indefinite article in the expression "have a good time"? Time is an uncountable noun, and we never say "what a beautiful weather!", but "what beautiful weather it is!"
Could anyone explain it to me?
Although time can be a mass noun, in this case it isn't. It means occasion or period, both of which are countable.
time sense 2:
And there's Dickens:
Time is uncountable when it describes the abstract concept, but it is countable when used in contexts such as this. We can have a good time, but we can also speak of good times and bad times. A good time makes a generic reference. That is, in the words of the ‘Longman Student Grammar of Spoken and Written English, it