It is basically the word "sigh" like when someone takes a deep breath in and out and you can hear it. "Sighed" is the past tense version of "sigh". Here is an example of "sigh" and "sighed":
Molly really wanted to sigh because of how disappointed she was with her brother.
Molly sighed, disappointed by what her brother had done.
Hope this helped! :D
In Alexie's case he outright states the true meaning for why he writes the poem or what the poem really means, which I really like. The title of this poem is also very interesting. Gentrification, or to gentrify, means to renovate and improve (especially a house or district) so that it conforms to middle-class taste.
