1. Without advance preparation
   - ad lib, spontaneously, impromptu

Encyclopedia: Ad libitum

• boundlessly
• boundlessness
• bounds
• bounteous
• bounteously
• bounteousness
• bountied
• bountiful
• bountifully
• bountifulness
• bounty
• bounty hunter
• bouquet
• bouquet garni
• bourbon
• Bourbon dynasty
• bourdon
• bourgeois
• bourgeoisie
• bourgeon
• Bourgogne
• bourguignon
• bourguignon sauce
• bourn
• bourne