THESAURUS
Volunteer
arbitrary, autonomous, autonomousness, autonomy, come forward, discretional, discretionary, do independently, do voluntarily, elective, free, free will, gratuitous, gratuitousness, independence, independent, need no prodding, nonmandatory, offered, optional, proffered, self-acting, self-action, self-active, self-activity, self-determination, self-determined, self-determining, spontaneity, spontaneous, spontaneousness, step forward, unasked, unbesought, unbidden, uncalled-for, uncoerced, uncompelled, unforced, unforcedness, uninfluenced, uninvited, unpressured, unprompted, unrequested, unrequired, unsolicited, unsought, voluntariness, voluntarism, voluntary, voluntaryism, volunteer militia, volunteer navy, volunteering, willful
ROGET THESAURUS
Volunteer
Will
VB
will, list, see fit, think fit, determine, enjoin, settle, volunteer, have a will of one's own, do what one chooses, have it all, one's own way, have one's will, have one's own way, use one's discretion, exercise one's discretion, take upon oneself, take one's own course, take the law into one's own hands, do of one's own accord, do upon one's own authority, originate.
Willingness
N
willingness, voluntariness, willing mind, heart, disposition, inclination, leaning, animus, frame of mind, humor, mood, vein, bent, penchant, aptitude, docility, docibleness, persuasibleness, persuasibility, pliability, geniality, cordiality, goodwill, alacrity, readiness, earnestness, forwardness, eagerness, asset, compliance, pleasure, gratuitous service, labor of love, volunteer, volunteering, willing, minded, fain, disposed, inclined, favorable, favorably- minded, favorably inclined, favorably disposed, nothing loth, in the vein, in the mood, in the humor, in the mind, ready, forward, earnest, eager, bent upon, predisposed, propense, docile, persuadable, persuasible, suasible, easily persuaded, facile, easy-going, tractable, genial, gracious, cordial, cheering, hearty, content, voluntary, gratuitous, spontaneous, unasked &c (ask), unforced, willingly, fain, freely, as lief, heart and soul, with pleasure, with all one's heart, with open arms, with good will, with right will, de bonne volonte, ex animo, con amore, heart in hand, nothing loth, without reluctance, of one's own accord, graciously, with a good grace, a la bonne heure, by all means, by all manner of means, to one's heart's content, yes.
VB
be willing, incline, lean to, mind, propend, had as lief, lend a willing ear, give a willing ear, turn a willing ear, have a half a mind to, have a great mind to, hold to, cling to, desire, see fit, think good, think proper, acquiesce, comply with, swallow the bait, nibble at the bait, gorge the hook, have no scruple of, make no scruple of, make no bones of, jump at, catch at, meet halfway, volunteer.
Undertaking
VB
undertake, engage in, embark in, launch into, plunge into, volunteer, apprentice oneself to, engage, contract, take upon oneself, take upon one's shoulders, devote oneself to, take up, take in hand, tackle, set about, go about, set to, fall to, set to work, launch forth, set up shop, put in hand, put in execution, set forward, break the neck of a business, be in, for, put one's hand to, put one's foot in, betake oneself to, turn one's hand to, go to do, begin one's, broach one's, institute one's, put one's hand to the plow, lay one's hand to the plow, put one's shoulder to the wheel, have in hand, have many irons in the fire.
Offer
VB
offer, proffer, present, tender, bid, propose, move, make a motion, make advances, start, invite, hold out, place in one's way, put forward, hawk about, offer for sale, press, lay at one's feet, offer oneself, present oneself, volunteer, come forward, be a candidate, stand for, bid for, seek, be at one's service, go a begging, bribe.