unaccountably 1. In an unaccountable manner. 2. For some unknown and usually puzzling reason. 3. Not able to be explained or understood: 'She said she felt unaccountably good when she got up this morning.' Related cutting-word units: castrat-; -cise, -cide; -ectomy; sec-, seg-; temno-; -... Found on http://www.wordinfo.info/words/index/info/view_unit/1803/5