Walter Mitty /wolˈ or wölˈtər mitˈi/

1. An ordinary person who indulges in escapist daydreams of fame, power, etc
2. An intrepid daydreamer

• have a bun in the oven
• have a care
• have a cob on
• have a crow to pluck with
• have a dekko
• have a finger in every pie
• have a fit
• have a friend at court
• have a game with
• have a go
• have-a-go
• have a go at
• have a good head on one's shoulders
• have a good mind
• have a good thing going
• have a good time
• have a great mind
• have a head like a sieve
• have a heart
• have a job to
• have all one's buttons
• have all one's buttons on
• have all one's eggs in one basket
• have all the answers
• have a load on