Sentence:  [T]he ebbed man, ne'er loved till ne'er worth love, / Comes deared by being lacked. This common body, / Like to a vagabond <WSD>flag</WSD> upon the stream, / Goes to and back, lackeying the varying tide, / To rot itself with motion. 
Meaning of the word marked with <WSD> tags:  Any of various plants with sword-shaped leaves, especially irises; specifically, "Iris pseudacorus".