甚
ジン, はなは.だ, はなは.だしい, じ
tremendously, very, great, exceedingly
JLPT1 G7 S9 F1961
As per 匹 (side by side) + 甘# (sweet/rich food contained in the mouth) → consume extreme amounts of sweet/rich food → *intensity*; *great degree* → *very*; *extreme*; *enormous*; *exceedingly*; *excessively*; *serious*; *outrageous*.
[Full Kanji Etymology List]