ad libitum /ad libˈi-təm or -tŭm/

1. At will, at pleasure
2. Extempore, impromptu (abbrev ad lib.)

ad-lib /ad-libˈ/ adverb

Spontaneously or freely

Impromptu, extemporized

To extemporize or speak without preparation, esp to fill up time

1. An improvised speech
2. A spontaneous (often humorous) remark

• well done
• well-done
• well drain
• well drains
• well-dressed
• well dressing
• well-earned
• welled
• well-educated
• well-endowed
• well enough
• well-entered
• well-famed
• well-favoured
• well-fed
• well-formed
• well-found
• well-founded
• well-given
• well-gotten
• well-graced
• well-groomed
• well-grounded
• wellhead
• wellheads