Sentence:  [The public] is so in awe of its own opinion, that it never dares to form any, but catches up the first idle rumour, lest it should be <WSD>behind-hand</WSD> in its judgment, and echoes it till it is deafened with the sound of its own voice. 
Meaning of the word marked with <WSD> tags:  Behind (someone or something moving, a trend, etc.), lagging behind, not keeping up.