Assuming “Kahiki” was “Tahiti”… Like Hawai’i / Hawaiki / Savai’i / Avaiki /… the etymology of “Kahiki” is so widely dispersed with cognates in every Moana language.
In Tahitian, “Tahiti” decomposes into:
“Ta-“ meaning “of, belonging to”
“Hiti” meaning “a border, an edge, an extremity of a place or a thing”
So “Tahiti” = “the faraway place”
Not only was Tahiti the name of the largest island in the group, it was also the farthest south, and farthest east. It is a term of distance before it is a national name.
In Samoa, the cognate of HITI is SI’I “fringe”, and reduplicated as SISI’I is “to make a fringe”; so ‘A-SI’I means “from the fringes”; it also means “to lift” as in the edge of a net or a cover; “little” and evocative of “sympathy”, “pity”. TASISI means “to draw up, as the pola mats forming the walls of a traditional Fale / house.” No such place as TAFITI. There is FITI, which is FIJI, and Fijians calls home VITI meaning “to push apart vegetation to peer ahead in the bush”.
In Hawaiian, KĀ can mean "of" and HIKI "an edge, border, extremity of a place, or thing".
In Tonga, HIKI “to edge with red feathers or other such decoration”; ‘A “of”; so ‘A-HIKI is “of the extreme edge”
Malay SISI “brink, edge” is closer to Sāmoan than either Tongan, or eastern Polynesia Hawaiian, Tahitian, Māori.
There are additional nuances of the root HI / SI that relate to sunbeams and fishing by hook and line and net.
Previously I have explored the etymology of TAGALOA / TANGAROA / KANALOA as relating to the vast net of a fisherman by comparing Polynesian and Austronesian roots TAGA / TANGA / KANA vs TANGGA “ladder, staircase, stairs” and LOA / ROA to RUAK “to spread out; to expand; to gape open”. The name KAHIKI seems like a fishing reference to the edges of a vast net, as well as the fish line of Māui and Tonga-fusi-fonua used to fish up lands from the depths of the Moana.
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