sententious (adj.)

c. 1200, "doctrine, authoritative teaching; an authoritative pronouncement," from Old French sentence "judgment, decision; meaning; aphorism, maxim; statement of authority" (12c.) and directly from Latin sententia "thought, way of thinking, opinion; judgment, decision," also "a thought expressed; aphorism, saying," an irregular (dissimilated) formation from sentientem, present participle of sentire "be of opinion, feel, perceive" (see sense (n.)). The meaning path is perhaps "way of perceiving in the mind" to "opinion" to "decision, judgment."

From early 14c. as "judgment rendered by God, or by one in authority;" also in the specific legal sense "a verdict, decision in a court." It is from late 14c. as "understanding, wisdom; edifying subject matter," a sense obsolete but frequent in Chaucer.

It is from late 14c. as "subject matter or content of a letter, book, speech, etc.," and also was used in reference to a passage in a written work. The sense of "grammatically complete statement in words" is attested from mid-15c. ("Meaning," then "meaning expressed in words.")

A sentence is a sound in itself on which other sounds called words may be strung. You may string words together without a sentence-sound to string them on just as you may tie clothes together by the sleeves and stretch them without a clothes line between two trees, but — it is bad for the clothes. [Robert Frost, letter to John T. Bartlett, Feb. 22, 1914]