superincumbent
adjective
su·per·in·cum·bent ˌsü-pər-in-ˈkəm-bənt 
: lying or resting and usually exerting pressure on something else
superincumbently adverb
Word History
Etymology
Latin superincumbent-, superincumbens, present participle of superincumbere to lie on top of, from super- + incumbere to lie down on — more at incumbent
First Known Use
1664, in the meaning defined above