Usually from Latin

ancient

facial

glacial

gracious

Grecian

precious

racial

social

special

vicious

acacia

atrocious

clinician

commercial

Confucian

deficient

delicious

efficient

ferocious

financial

judicial

judicious

logician

magician

mortician

musician

official

optician

patrician

physician

precocious

proficient

sufficient

suspicion

tactician

technician

tenacious

alopecia

artificial

beneficial

diagnostician

electrician

geriatrician

mathematician

politician

statistician

superficial

theoretician