A primitive root; probably to look askant, i.e. (figuratively) be jealous -- leap.
Englishman's Concordance
1) (Piel) to watch stealthily or with envious hostility, watch with enmity, watch with envy Part of Speech: verb A Related Word by BDB/Strong’s Number: a primitive root Same Word by TWOT Number: 2206
Brown-Driver-Briggs
[רָצַד] verb Pi`elwatch stealthily, or with envious hostility (Arabic watch or wait (often lie in wait) for; ירצר Ecclus 14:22 observe stealthily, so once Aramaic רְצַר LevyNHWB iv. 464); — only Imperfect2masculine plural תְּרַצְּדוּןPsalm 68:17 (figurative of mountains, with accusative).
Psalm 68:16 HEB: לָ֤מָּה ׀ תְּֽרַצְּדוּן֮ הָרִ֪ים גַּבְנֻ֫נִּ֥ים NAS: Why do you look with envy, O mountains KJV:Why leap ye, ye high hills? INT: Why look mountains with peaks