啧 is a simplified Chinese hanzi, listed here under the keyword “interjection of approval or admiration”. It is built from 口 (mouth) and 责 (one's responsibility).
On KumiJi Glyph Explorer, open the parts search and type “mouth” + “one's responsibility”. 啧 is among the results, together with every other character containing the same shapes.
Open 啧 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.