綻
タン, ほころ.びる
be rent, ripped, unravel, run, begin to open, smile
JLPT0 G7 S14 F5000
定# fix (straight) in place + 糸 thread → mend an unraveling garment by fixing loose fabric in place → *unravel*; *come apart at the seams*; *ripped* (seams). Also, *bloom* and *smile* (← open up).
[Full Kanji Etymology List]