Abarim Publications' online Biblical Hebrew Dictionary
The root-verb רצה (rasa) means to be pleased with, be favorable to, or accept favorably. HAW Theological Wordbook of the Old Testament reports that this verb is a "very ancient Wets-Semitic root," found in many cognates, in a letter from Amarna (1370 BC) and all over the Bible. This verb is used to indicate God's response towards the Servant (Isaiah 42:1) or of people to people (Malachi 1:8). It's used to indicate acceptability of offerings to God (2 Samuel 24:23), to indicate sadism (Psalm 40:14), or to enjoy rest like a Sabbath (Leviticus 26:34).
This verb comes with one derivative, namely the masculine noun רצון (rason), meaning goodwill, favor, pleasure of acceptance (Deuteronomy 33:16, Exodus 28:38, Ezra 10:11).