God uses the word 'Adultery' for indulging in idolatry in the verse below Jeremiah 3:8-9:
ח וָאֵרֶא, כִּי עַל-כָּל-אֹדוֹת אֲשֶׁר נִאֲפָה מְשֻׁבָה יִשְׂרָאֵל, שִׁלַּחְתִּיהָ, וָאֶתֵּן אֶת-סֵפֶר כְּרִיתֻתֶיהָ אֵלֶיהָ; וְלֹא יָרְאָה בֹּגֵדָה יְהוּדָה, אֲחוֹתָהּ--וַתֵּלֶךְ, וַתִּזֶן גַּם-הִיא. וְהָיָה מִקֹּל זְנוּתָהּ, וַתֶּחֱנַף אֶת-הָאָרֶץ; וַתִּנְאַף אֶת-הָאֶבֶן, וְאֶת-הָעֵץ.
emphasis added to show Adultery with Idols
8 And I saw, when, forasmuch as backsliding Israel had committed adultery, I had put her away and given her a bill of divorcement, that yet treacherous Judah her sister feared not; but she also went and played the harlot;
9 and it came to pass through the lightness of her harlotry, that the land was polluted, and she committed adultery with stones and with stocks;
Why such a strange word or rather unusual euphemism was used for breaking the covenant, Hence wanted to know the significance of using this particular word?