换言之
huànyánzhī · HSK 7
word
换 swap + 言 words + 之 it = swap the words for it, i.e. in other words
换 means swap or change, 言 means words or speech, and 之 is a classical it. Putting it together: re-state the same idea with swapped-out words. huànyánzhī = in other words.
换 — hand radical 扌 + 奂 huàn (phonetic)
换 is a semantic-phonetic compound. The hand radical 扌 signals an action done with the hands, while 奂 supplies the sound huàn. The original sense of exchanging or swapping things by hand extended naturally to broader meanings like 'change' or 'replace'.
之 — foot 止 above ground line 一
Originally a pictograph of a foot (止) stepping forward from a baseline, meaning 'to go' or 'to proceed'. Over time the concrete 'going' sense faded, and 之 was borrowed as a grammatical particle marking possession ('of') or as a pronoun ('it'), which became its dominant use in Classical Chinese.