The classical phrase "赳赳武夫" means a brave, martial warrior.
Tips
history
赳 never stands alone; it appears only doubled as 赳赳 (valiant), famous from the Book of Songs phrase 赳赳武夫. It joins the walk radical 走 with the old phonetic 丩.
register
Classical and bound — modern use is essentially the fixed reduplication 赳赳.