journalist (n.)

mid-14c., "book of church services," from Anglo-French jurnal, from Old French jornel, "a day; time; a day's travel or work" (12c., Modern French journal), properly "that which takes place daily," noun use of adjective meaning "daily, of the day," from Late Latin diurnalis "daily," from Latin dies "day," from PIE root *dyeu- "to shine."

The meaning "book for inventories and daily accounts" is from late 15c. in English (14c. in French); that of "personal diary" is c. 1600, also from a sense developed in French. Meaning "daily publication" is from 1728. Classical Latin used diurnus for "of the day, by day," and also as a noun, "account-book, day-book."

Initial -d- in Latin usually remains in French, but according to Brachet, when it is followed by an -iu-, the -i- becomes consonantized as a -j- "and eventually ejects the d." He also cites jusque from de-usque.

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.