Definition of "significant"

It was well said of Plotinus, that the stars were significant, but not efficient.

1614, Walter Ralegh [i.e., Walter Raleigh], The Historie of the World […], London: […] William Stansby for Walter Burre, […], (please specify |book=1 to 5)

As evening came on, it grew prematurely dark and cloudy; while the waves acquired that dull indigo tint so significant of ugly weather.

1856, Charles Dickens, Wilkie Collins, chapter III, in The Wreck of the Golden Mary, part two, page 99

The “little green men”—faces covered, wearing unmarked olive uniforms, speaking Russian and using Russian weapons—have played a significant role in both the occupation of Crimea and the civil war in eastern Ukraine.196

2015, Shane R. Reeves, David Wallace, “The Combatant Status of the “Little Green Men” and Other Participants in the Ukraine Conflict”, in International Law Studies, US Naval War College‎, volume 91, number 361, Stockton Center for the Study of International Law, page 393

In dumb significants proclaim your thoughts.

1591 (date written), William Shakespeare, “The First Part of Henry the Sixt”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene iv]

And in my glass significants there are

a. 1850, William Wordsworth, The Egyptian Maid