1. Rolling on the floor laughing; indicates that something is thought to be highly amusing
   - ROFL

Encyclopedia: ROTFL

• unsteadily
• unsteadiness
• unsteady
• unstep
• unsterilised
• unsterilized
• unstick
• unstilted
• unstimulated
• unstimulating
• unstinted
• unstinting
• unstintingly
• unstirred
• unstop
• unstoppable
• unstoppered
• unstrain
• unstrained
• unstrap
• unstratified
• unstratified language
• unstressed
• unstring
• unstructured