Old English cnocian (West Saxon cnucian), "to pound, beat; knock (on a door)," likely of imitative origin. Figurative meaning "deprecate, put down" is from 1892. Related: Knocked; knocking. Of engines from 1869. To knock back (a drink) "swallow quickly or at a gulp" is from 1931. Many phrases are in reference to the auctioneer's hammer, for example knock down (v.) "dispose of (something) at auction" (1760).
c. 1300, "in circumference, in a circle, on every side," from phrase on round; see a- (1) + round (adj.). It was rare before 1600. In the sense of "here and there with no fixed direction" it is attested from 1776 in American English (British English prefers about).
As a preposition, "on or along a circuit," from late 14c.; "on all sides, encircling, about" from 1660s; of time, by 1873. To have been around "gained worldly experience" is from 1927, U.S. colloquial; to get around to it is from 1864.
<a href="https://www.etymonline.com/word/knockabout">Etymology of knockabout by etymonline</a>
Harper, D. (n.d.). Etymology of knockabout. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/knockabout