present participle of add on

(medicine) Initialism of Adverse Drug Effect. / (medicine) Initialism of antibody-dependent enhancement.

plural of AD

(physics, mathematics, cosmology) Initialism of anti de Sitter.

plural of Adelie

As much as desired, to one's fill, without restriction.

Characterized by doing something ad libitum.

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

Extemporaneous, impromptu.

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