What does the word “glideth” in the fourth line mean?

Reading comprehension: Read the quoted parts carefully and answer the questions in English. Write your answer in the corresponding space on the answer sheet. “Never did sun more beautifully steep
In his first splendor, valley, rock, or hill;
Ne’er saw I, never felt, a calm so deep!
The river glideth at his own sweet will:
Dear God! The very houses seem asleep;
And all that mighty heart is lying still!”
(William Wordsworth’s sonnet: “Composed upon Westminster Bridge” September 3, 1802)
What does the word “glideth” in the fourth line mean?
【正确答案】：

TO MOVE SMOOTHLY AND QUIETLY, AS IF NO EFFORT WAS BEING MADE.

【题目解析】：这个词的意思是：平稳而安静地移动，好像丝毫不费力。