= onomatopoeia (This is the correct spelling.) = Figure of speech that copies natural sounds. For example, the word 'cuckoo' imitates the sound that the cuckoo makes. Such words as bang, crash, ripple, smash, splash, and thump are said to be onomatopoeic. Onomatopoeia works differently in different languages, the English bow-wow for a sound made by dogs being paralleled by the French oua, oua. Onomatopoeia may be built into prose or verse, as in 'a sudden sizzling sound', the s and zsounds used to suggest frying.
The formation or use of words such as buzz or murmur that imitate the sounds associated with the objects or actions they refer to.
Onomatopoeia is a word that phonetically imitates, resembles, or suggests the sound that it describes. For example, words like "buzz," "meow," and "splash" are considered onomatopoeias because they sound like the noises they represent.
No, "scoffed" is not an onomatopoeia. An onomatopoeia is a word that phonetically imitates, resembles, or suggests the sound it describes, like "buzz" or "hiss". "Scoffed" does not resemble the sound it describes.
Figure of speech is a literary device used as rhetoric device in expository speech by use of:metaphors,hyperbole,asyndetons,hyperbaton,polyptoton,alliterations,similes,hyperboles,anaphora,diatyposis,onomotopia and other forceful figures to add force and beauty in speech.
The sounds of the letter o in the second line of the poem, know, older, and flow, asssonate. See also the phrase muddy bosom turn. Whether or not the repetition of the long "I" sound at the beginning of nearly every line can be considered alliteration is debatable but only the line "Ancient, dusky rivers" does not begin with the sound. The word "rivers" might be considered onomotopoetic as it sounds like the flow of water it describes, but I see no attempt at onomotopia in the poem.