In John Keats's poem La Belle Dame sans Merci, he writes, "She looked at me as she did love,/ And made sweet moan." Keats seems to use the word "moan" in a similar sense in the third stanza of Ode to Psyche: "Nor virgin-choir to make delicious moan/ Upon the midnight hours." In the fourth stanza, Keats again uses the phrase make moan. I noticed that in other poems, Keats employs the word "moan" in the typical sense. For instance, in thirty-third stanza of The Eve of St. Agnes, he describes Madeline uttering a "soft moan" as she gains consciousness. This usage seems more or less descriptive.
I was surprised that the very stanza where I found this example also had a reference to the song "La belle dame sans mercy." I read that Keats wrote The Eve of Saint Agnes before La Belle Dame sans Merci, so I know that he is not referencing himself. But I find it odd that Keats would use the phrase "make moan" in more than one of his poems. Perhaps this is a Spenserian usage, because Spenser's Faerie Queene deeply influenced Keats, and Keats deliberately used archaic words like Paynim to mean a (usually Muslim) non-Christian or wight to mean "person" (as did many poets, but Keats seemed particularly connected to Spenser).
Some online forums such as this one attach a sexual meaning to the word "moan." While these websites aren't authorities on Keats or English usage, I have to admit that the word "moan" certainly suggests sexual activity, just as other questions about "moan" on English Stack Exchange.
Another website claims that the phrase "made sweet moan" is just for poetic assonance. I will post the other two links as a comment because this is my first question, and I lack the reputation needed to embed more than two links.
I doubt that Keats intended the word to be sexual – it makes little sense in the context of "virgin-choir" or the overall mood of these poems. I was just wondering if there was an obscure or archaic usage of "moan" that would make sense in context. Thank you!
Best Answer
TL;DR: The phrase make moan was once quite common, so its repeated appearance in Keats' poetry isn't surprising. His exact meaning is open to interpretation, and probably isn't always the same.
The Oxford English Dictionary lists make (one's) moan as a previously common form, with two possible definitions.
So I don't think it's particularly surprising that Keats, writing in the early nineteenth century, used the phrase "make moan" multiple times.
Keats' intended meaning for any particular instance probably varies and may be intentionally ambiguous, though it is probably closer to definition b. than definition a. in the lines you reference. Certainly the adjectives "sweet" and "delicious" suggest that the moans were pleasing to the hearer, which seems much more likely for requests, prayers, or entreaties than for lamentations or complaints.
This seems clearest in Ode to Psyche where both instances of "making moan" can easily be read as "saying prayers/entreating [the Goddess Psyche]". The deliciousness of the virgins' moans is fairly understandable in this context, as prayers are typically understood to be pleasing to their objects (even for gods who don't require literal sacrifice of delicious food, as in this blog post).
The line in La Belle Dame sans Merci is a little harder to parse. The phrase appears during what could be seen as a courtship, a seduction, or an abduction and rape; which way you see the overall situation will determine whether you think she is lamenting/complaining, entreating/requesting (begging?), or just making an inarticulate sound of some sort. Note that later in the poem "she wept and sighed full sore"—immediately after, we are told, she fed the protagonist sweet treats and "said—/‘I love thee true’."
It is also entirely consistent with the OED's definitions that some of these usages were "coloured by association with sense 2" (which is essentially the same as the one @HotLicks cited in the comments):
In which case I think it is reasonable to conclude that "sweet" and "delicious" moans are, indeed, intended to be ambiguous with regard to sexual connotations. This interpretation seems especially likely in the case of La Belle Dame sans Merci, which explicitly deals with love and kisses.