secularist n.

"exclusive attention to the present life and its duties; doctrine that morality should be based on the well-being of man in the present life, without regard to religious belief or a hereafter," 1843, from secular + -ism.

Secularity (late 14c., seculerte ) was used for "civil or temporal power, the business of layman life; quality or condition of being secular" (from Old French secularite and Medieval Latin sæcularitas).

word-forming element meaning "one who does or makes," also used to indicate adherence to a certain doctrine or custom, from French -iste and directly from Latin -ista (source also of Spanish, Portuguese, Italian -ista), from Greek agent-noun ending -istes, which is from -is-, ending of the stem of verbs in -izein, + agential suffix -tes.

Variant -ister (as in chorister, barrister) is from Old French -istre, on false analogy of ministre. Variant -ista is from Spanish, popularized in American English 1970s by names of Latin-American revolutionary movements.