efficacious
/ˌɛfɪˈkeɪʃəs/
adjective
formal
- (of something inanimate or abstract) successful in producing a desired or intended result; effective."this treatment was efficacious in some cases"
efficacious
extrapolate
extricate
engender
supplication
quid pro quo /ˌkwɪd prəʊ ˈkwəʊ/ noun noun : quid pro quo ; plural noun : quid pro quos a favour or advantage granted in return for...