To speak rhetorically or in a loud, theatrical manner. The actor declaimed his lines with great passion during the rehearsal.
To deliver a formal recitation, especially as an exercise in rhetoric or elocution. The student was asked to declaim a passage from Shakespeare for the class.
To utter or recite something in a forceful, pompous, or impassioned manner. Standing on the steps of the courthouse, the activist declaimed her demands to the gathered crowd.