Our habitat: threshold
One does not have to be a specialist to suggest that threshold is either a disguised compound or that it contains a root and some impenetrable suffix. Disguised compounds are words like bridal (originally, bride + ale but now not even a noun as in the past, because –al was taken for the suffix of an adjective) or barn, a blend of the words for “barley,” of which only b is extant, and Old Engl. earn “house.”