某

Bottom tree radical (Kangxi #75) — the indexing radical of 某. Together with the fruit on top: a fruit-laden tree, originally a specific plum tree. By a chain of phonetic loan, 某 was borrowed for the indefinite pronoun 'a certain (one), some, so-and-so'; the tree meaning was preserved by adding 木 to make 梅 'plum'. So 某 is a phantom: the original tree-name now carries the indefinite reference.

Top 甘 — graphically the 'sweet' character (a mouth with something inside), but in 某 it is the residue of an older 口-shaped fruit sitting on the tree below. The original 某 was a pictograph of a fruit-bearing tree, the etymological root of 梅 'plum tree'. The 'sweet' reading of 甘 is not active here; treat as the fruit hanging on the branches.