得体 is read as えたい (etai) and means nature.
えたい
etai
えたいがしれない
not knowing the true nature
えたいのしれない
strange
たいとく
mastery
とくい
one's strong point
とく
rebirth in paradise, entering nirvana
うる
to be able to ...
とくてん
scoring
える
to be able to ..., can ...
とくする
to make a profit
とくいさき
(regular) customer
とくしつ
advantages and disadvantages
とくど
becoming a monk