dream ‧ er /ˈdriːmə $ -ər/ BrE AmE noun [countable]
[ Word Family: adjective : dream, ↑ dreamless , ↑ dreamy ; noun : ↑ dream , ↑ dreamer ; verb : ↑ dream ; adverb : ↑ dreamily ]
1 . someone who has ideas or plans that are not practical:
She was a dreamer – not pragmatic.
2 . someone who dreams while they are asleep