o·ver·board 
(ōvər-bôrd′)
(ōvər-bôrd′)adv.
Idiom: Over or as if over the side of a boat or ship.
go overboard
To go to extremes, especially as a result of enthusiasm.
- four-in-hand
- four-leaf clover
- four-letter word
- four-o'clock
- four-peat
- fourpenny nail
- fourplex
- four-poster
- fourragère
- fourscore
- foursome
- foursquare
- foursquarely
- four-star
- fourteen
- fourteenth
- fourth
- fourth dimension
- fourth estate
- Fourth of July
- fourth quantum number
- fourth wall
- Fourth World
- Fourth-World
- four-way