1. Absence or a lack of movements: Acinesia is a partial or total loss of muscle movements because of peripheral or central nervous system abnormalities.

Mable's acinesia was most obvious when she was trying to swim.

2. An absence of or a decrease of voluntary motion that may range from moderate inactivity to almost complete immobility: The doctor warned Marcos that prolonged use of the wheelchair could result in acinesia of his legs.

With insects, akinesia is a lack of immobility that can be caused by damage to or a loss of sensory organs; such as, the antennae.