頑
ガン, かたく

stubborn, foolish, firmly

JLPT1 G7 S13 F1247

As per 元# (rounded/oval head) + 頁 head → rounded/oval head → *stubborn* (← make no progress in convincing another ← circular discussion going round and round in a person's head; compare 願) → *stout*. 頑 was devised to convey the original sense of 元, but it too acquired extended meanings.

[Full Kanji Etymology List]