biennial /bī-enˈi-əl or -enˈyəl/

1. Lasting two years
2. Happening or appearing once in two years

1. A plant that flowers and fruits only in its second year, then dies
2. An event taking place or being celebrated every two years

• out of tune
• out of use
• out of warrant
• out of whack
• out of whole cloth
• out of work
• out-of-work
• out on a limb
• out on one's ear
• out on one's feet
• out out the window
• out-over
• out-owre
• outpace
• outpaced
• outpaces
• outpacing
• out-paramour
• out-paramoured
• out-paramouring
• out-paramours
• out-parish
• out-parishes
• outpart
• outparts