1. Not capable of being changed into something else
   - inconvertible

See also: incommutable

• xystus
• XYY
• y
• Y chromosome
• y'all
• y'know
• y-axis
• Y-fronts
• Y-linked gene
• Y-shaped
• Y2K
• Y2K compliant
• ya
• yabber
• yacca
• yacca podocarp
• yacht
• yacht chair
• yacht club
• yacht race
• yachting
• yachting cap
• yachtsman
• yachtswoman
• yack