Adynamic

[ædai'næmik]

(adj.) lacking strength or vigor .

Checker: McDonald--From WordNet

(a.) Pertaining to, or characterized by, debility of the vital powers; weak.

(a.) Characterized by the absence of power or force.

Checker: Vivian

adj. without strength: (phys.) characterised by the absence of force.

Checked by Erwin