Where does “existimo” come from?

existimo (Latin) comes from Latin aestimō, from Latin aestumo — to value, rate, esteem.

Ancestry of “existimo”, step by step

Step	Language	Word	Meaning
1	Latin	aestimō	—
2	Latin	aestumo	to value, rate, esteem

existimo — Etymology, Origin & Word History | Etymology Explorer