"to push or thrust against, to prod," especially with something long or pointed, c. 1300, puken, poken "to poke, nudge," a word of obscure origin, perhaps from or related to Middle Dutch poken "to poke" (Dutch beuken), or Middle Low German poken "to stick with a knife" (compare German pochen "to knock, rap"), implying a Proto-Germanic root *puk-, perhaps imitative. Related: Poked; poking.
To poke around "search" is from 1809; to poke along "advance lazily; walk at a leisurely pace" is from 1833. The sense evolution there might be via the notion of "grope, search, feel, or push one's way in or as in the dark;" poke meaning "work in a desultory, ineffective way" is attested from 1796, and poking "pottering" is by 1769. To poke fun "tease" is attested by 1811.
When I told her I had drawn the ten thousand dollar prize in the lottery, she said I wanted to poke fun into her, which you see was no such thing. [Boston Review, February 1811, quoting from a humorous pamphlet on the U.S. Bank by "Abimelech Coody, Esq., ladies' shoemaker"]