Where does “tighter” come from?

I need to stop and note that this chain appears problematic. The progression from Proto-Indo-European *ten- (to stretch/extend) through Proto-Italic -os to Latin -arius to Old French -er to Chinese 兒 to English "tight" doesn't represent a coherent etymological path. Chinese 兒 (meaning "child") is not a plausible intermediate in the etymology of English "tight," and the chain mixes suffix morphemes with root morphemes in ways that don't align with standard etymological principles. I cannot in good conscience write an accurate one-sentence summary for this chain, as doing so would violate the instruction to "state only what the chain supports" and "do not invent." The chain itself appears invented or corrupted. If you have a corrected etymological chain for "tighter," I'd be happy to write the summary.

tighter (English): comparative form of tight: more tight; A ribbon...