hobnobyoudaoicibaDictYouDict[hobnob 词源字典]
hobnob: [18] In Shakespeare’s Twelfth Night, Sir Toby Belch says ‘Hob, nob, is his word: give’t or take’t’; from which it has been deduced that the hob of hobnob represents have and that the nob represents the now obsolete nave ‘not have’ (formed in the Old English period by adding the negative particle ne to have). In Middle English these would have been habbe and nabbe.

When hobnob first appears as a verb, in the mid 18th century, it means ‘drink together’ – perhaps from the notion of buying alternate rounds of drinks, or drinking toasts to each other in turn. The modern sense ‘associate familiarly, socialize’ is not recorded before the early 19th century.
=> have[hobnob etymology, hobnob origin, 英语词源]
hobnob (v.)youdaoicibaDictYouDict
1763, "to drink to each other," from hob and nob (1756) "to toast each other by turns, to buy alternate rounds of drinks," from c. 1550 hab nab "to have or have not, hit or miss," probably ultimately from Old English habban, nabban "have, not have," with the negative particle ne- attached, as was customary. Modern sense of "socialize" is 1866. Related: Hobnobbed; hobnobbing.