This is the 12182nd most frequent Portuguese word.
responderem
"Responderem" means "to respond" or "to answer" (in the third person plural, subjunctive or future form, in Portuguese).
Here, 'respondam' is used in the subjunctive form, indicating a desired action.
Espero que eles respondam às perguntas de maneira clara.
I hope they respond to the questions clearly.
In this sentence, 'responderem' is used in the future subjunctive, expressed within a conditional context.
Se eles responderem ao e-mail, continuaremos a discussão.
If they respond to the email, we will continue the discussion.
The word 'responderem' is used in the infinitive form tied to an auxiliary verb to indicate an action to perform.