simple past tense and past participle of add up

(Internet, advertising) An advertisement which extends horizontally across a web-page. / An advertisement on a banner.

simple past tense and past participle of ad lib

Use of ad hoc or improvised reasoning. / (computing) Arbitrary decision rules sometimes included in artificially intelligent software to simulate the unexpectedness in human reasoning.

Third-person singular simple present indicative form of ad lib

A person who ad-libs, particularly one who is well known for skill in ad-libbing.

To perform without script. / To perform without preparation. / To perform extemporaneously.

At pleasure. / At will. / To whatever extent. / Extemporaneously.

Misspelling of ad hominem.

Extemporaneous, impromptu.