great deal is a noun meaning "(often followed by `of') a large number or amount or extent". It carries one recorded sense.
(often followed by `of') a large number or amount or extent
“a batch of letters”
“a deal of trouble”
“a lot of money”
“he made a mint on the stock market”
“see the rest of the winners in our huge passel of photos”
“it must have cost plenty”
“a slew of journalists”
“a wad of money”
Definitions, synonyms and semantic relations for great deal come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.