A nonspecific term of waning popularity variously defined as:
(1) Freedom from pain; ~analgesia
(2) Freedom from fatigue
(3) Lack of effort
Aponia got 257 hits on 25.12.2015. Most of those hits are in secondary or non-English language literature or refer to a proprietary GPS system, a musical group, or a proprietary facial cream. Aponia is not used in the working medical parlance and should be retired.