忍 is a Chinese hanzi, listed here under the keyword “endure”. It is built from 刃 (edged tool) and 心 (heart). It appears as a component in 6 other characters in this index.
On KumiJi Glyph Explorer, open the parts search and type “edged tool” + “heart”. 忍 is among the results, together with every other character containing the same shapes.
Open 忍 in the interactive kanji search
to expand every part down to its smallest pieces, add your own names and mnemonic stories,
or search for other characters by their parts.