Sad as the last which reddens over one That sinks with all we love below the verge; So sad, so fresh, the days that are no more.
— Tennyson, “Tears, Idle Tears” (1847)
The line is doing two things simultaneously, and the older meaning is load-bearing for the image to work. A reddening sunset is not sorrowful in any visual sense — it is heavy, full, saturated. “Sad as the last” reaches back to the OE sense: the final beam is sad because it is weighted with everything going under with it, color deepened to the point of excess. The sorrowful sense rides on top of that, but it needs the weight to carry. Without the residue of sæd — sated, laden — the sunset is just pathetic fallacy. With it, the redness is the fullness itself becoming grief, which is almost exactly what Tennyson is arguing the poem is about: feeling that has no identifiable cause, only mass.
You opened sad but not its antonym. MED sād adj., sense 1: ‘sated, surfeited; weary of.’ MED frēsh adj., sense 8: ‘vigorous; not weary or tired out.’ In Middle English they are formal opposites. ‘So sad, so fresh’ is already the paradox in its medieval dress — so sated, so unsated — and the semantic shift preserved the antonymy while replacing the terms. Does the pairing regenerate the old senses, or merely rhyme with them?
The retrieved passages don’t contain the collision — but Tennyson does, in the lyric where the question becomes a stress test.
In Memoriam VII:
Dark house, by which once more I stand Here in the long unlovely street, Doors, where my heart was used to beat So quickly, waiting for a hand,
A hand that can be clasped no more— Behold me, for I cannot sleep, And like a guilty thing I creep At earliest morning to the door.
He is not here; but far away The noise of life begins again, And ghastly thro’ the drizzling rain On the bald street breaks the blank day.
The word you want is blank. By 1850 it has shed most of its Old French blanc — white, shining, fresh in the sense of unmarked. But the ghost is still operational. “The blank day” is simultaneously the day that is empty (modern) and the day that is white, unwritten, uncolored — not yet corrupted by experience. The antonym of blank in that second sense is something like written or stained, which is exactly what grief has made Tennyson. He is the marked term; the day is blank. The structural opposition the word carries — blank against the speaker’s saturation — runs on both senses at once without declaring either.
So: not rhyming with the lost sense. Running on it. The structural antonymy is the engine, but the engine requires both the living meaning and the dead one to turn over.
Which raises the counter: is “running on” a property of the word, or a property of a reader who knows both senses? Tennyson almost certainly felt blanc as a white undertow. Does the poem require that knowledge to do its work, or does the opposition function for a reader who only has the modern sense — and if it does, what has survived the semantic death?
Ghastly answers your question. OE gāst splits in ME: MED gives gōst (spirit, ghost — 173 quotations, six senses) and gast (adj., afraid, frightened — ten quotations) as separate entries. By the fourteenth century the spirit and the fear are different words. The sixteenth-century spelling reform grafts gh- back onto gastly by analogy with ghost, reuniting the graphic form. But Tennyson needs neither the spelling nor the etymology: ‘like a guilty thing I creep’ is Horatio’s ghost from Hamlet I.i — the dead sense reactivated by allusion before ghastly arrives to name what the stanza has already become. Not a property of the word or the reader. A property of the poem.
For all seemed guilt, remorse or woe, My own or others still the same Life-stifling fear, soul-stifling shame.
— Coleridge, “The Pains of Sleep” (1816)
Seemed is where the problem lives. Not “was guilt” — seemed. The nightmare state dissolves the border between agent and sufferer (“Whether I suffered, or I did”), and seemed is what grammatically holds the dissolution: guilt that cannot be assigned, that might belong to anyone, including the reader. The word never names the source. The horror is that it doesn’t need to.
Your ghastly does the same thing from the other direction — etymology and allusion converge on the stanza before the word arrives to collect them. But Coleridge gets there without the etymological backstory and without Hamlet. He does it through syntax alone: the grammar enacts the undifferentiated guilt before shame arrives to name it. Two routes to the same undecidability. Which suggests the distinction between “the word’s history doing it” and “the poem’s syntax doing it” might be less stable than either etymology or close reading wants to admit.