casuist
noun
ca·su·ist ˈka-zhü-ist 
ˈkazh-wist
: one skilled in or given to casuistry
casuistic
ˌka-zhə-ˈwi-stik
adjective or casuistical
ˌka-zhə-ˈwi-sti-kəl
Word History
Etymology
probably from Spanish casuista, from Latin casus fall, chance — more at case
First Known Use
1609, in the meaning defined above