只是
zhǐshì · HSK 3
only
只 = only/just + 是 = to be → merely / just simply is
只 by itself means 'only/just'; 是 is the copula 'to be'. Together 只是 literally reads as 'just is' — used to soften a statement or restrict it to 'merely / simply'.
只 — mouth 口 + bird tail 八
Originally a pictograph showing a bird (口 as body) with its tail feathers (八) spread, meaning a single bird. It was later borrowed phonetically to write the grammatical particle and adverb meaning 'only' or 'just,' which became its dominant modern use.
是 — sun 日 + 正 (correct/upright)
Originally a compound suggesting 'the sun 日 directly overhead'—straight, correct, true. From this concrete sense of 'right' or 'this very thing,' 是 came to mean 'this' as a demonstrative, and later the modern copula 'to be / is.' The 'correct' meaning survives in words like 是非 (right and wrong).