亟 is a Chinese hanzi, listed here under the keyword “urgently”. It is built from 了 (to finish), 叹 (sigh) and 一 (one). It appears as a component in 2 other characters in this index.
On KumiJi Glyph Explorer, open the parts search and type “to finish” + “sigh” + “one”. 亟 is among the results, together with every other character containing the same shapes.
Open 亟 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.