Synonyms for firmly

adamantly, assertively, confidently, determinedly, emphatically, enduringly, fixedly, immovably, inflexibly, peremptorily, resolutely, rigidly, robustly, securely, solidly, staunchly, steadfastly, stoutly, stringently, strongly, sturdily, tenaciously, unalterably, uncompromisingly, undeviatingly, unflinchingly, unshakeably, unswervingly, unwaveringly