let's not fall out : QUARREL, argue, row, fight, squabble, bicker, have words, disagree, be at odds, clash, wrangle, cross swords, lock horns, be at loggerheads, be at each other's throats; informal scrap, argufy, argy-bargy.
the soldiers fell out : MOVE OUT OF FORMATION, move out of line; stand at ease.
2192; headword