showing sustained enthusiastic action with unflagging vitality; "an indefatigable advocate of equal rights"; "a tireless worker"; "unflagging pursuit of excellence"
not capable of being conquered or vanquished or overcome; "a tribute to his courage...and his unconquerable will"- R.E.Danielson; "faced unconquerable difficulties"
a procession (of wagons or mules or camels) traveling together in single file; "we were part of a caravan of almost a thousand camels"; "they joined the wagon train for safety"
someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous); "the speaker at commencement"; "an utterer of useful maxims"
the presiding officer of a deliberative assembly; "the leader of the majority party is the Speaker of the House of Representatives"