no holds barred

Old English haldan (Anglian), healdan (West Saxon), "to contain, grasp; retain; foster, cherish," class VII strong verb (past tense heold, past participle healden), from Proto-Germanic *haldanan (cf. Old Saxon haldan, Old Frisian halda, Old Norse halda, Dutch houden, German halten "to hold," Gothic haldan "to tend"), originally "to keep, tend, watch over" (as cattle), later "to have." Ancestral sense is preserved in behold. The original past participle holden was replaced by held beginning 16c., but survives in some legal jargon and in beholden.

Hold back is 1530s, transitive; 1570s, intransitive; hold off is early 15c., transitive; c.1600, intransitive; hold out is 1520s as "to stretch forth," 1580s as "to resist pressure." Hold on is early 13c. as "to maintain one’s course," 1830 as "to keep one’s grip on something," 1846 as an order to wait or stop. To hold (one's) tongue "be silent" is from c.1300. To hold (one's) own is from early 14c. To hold (someone's) hand "give moral support" is from 1935. Phrase hold your horses "be patient" is from 1844. To have and to hold have been paired alliteratively since at least c.1200, originally of marriage but also of real estate.