Verbs

(v)throw inadd as an extra or as a gratuity
(v)drop out, give up, fall by the wayside, drop by the wayside, throw in, throw in the towel, quit, chuck up the spongegive up in the face of defeat of lacking hope; admit defeat“In the second round, the challenger gave up”
(v)interject, come in, interpose, put in, throw in, injectto insert between other elements“She interjected clever remarks”