Answer:
The use of the word "muttering" in this context suggests a feeling of discontent or dissatisfaction. It implies that the speaker is moving through the streets, possibly alone or in a state of thought or reflection, and experiencing some level of dissatisfaction or frustration with their surroundings. The street itself is described as a "retreat" and the line "of restless nights in one-night cheap hotels" adds to the sense of transience and ennui. Overall, the use of words and phrases like "half-deserted", "one-night cheap hotels", and "insidious intent" convey a sense of discomfort and unease, which the word "muttering" complements by suggesting that the speaker is grumbling or murmuring under their breath.