Origin: 1555–65; < LL
catēchista < Gk
katēchist
s, equiv. to
katēch(
eîn) to teach by word of mouth, orig. to din down, i.e. to get results by shouting (
kat- cata- +
ēcheîn to sound) +
istēs -ist 
Related forms: cat⋅e⋅chis⋅tic, cat⋅e⋅chis⋅ti⋅cal, adjective
cat⋅e⋅chis⋅ti⋅cal⋅ly, adverb