Adverbial has 2 senses

• a great deal(r = adv.all) a good deal, a lot, lots, much, very much - to a very great degree or extent; "I feel a lot better"; "she was very much interested"; "this would help a great deal"; "we enjoyed ourselves very much"
• a great deal(r = adv.all) much, often - frequently or in great quantities; "I don't drink much"; "I don't travel much"