This is the 5797th most frequent Japanese word.
はう
"はう" means "to crawl" or "to creep."
The term "はう" is used here metaphorically, suggesting extreme emotion.
彼はテストに合格したと聞いて、はうほど喜びました。
Upon hearing that he passed the test, he was overjoyed to the point of crawling.
"はう" here literally means "to crawl" involving physical movement.
赤ん坊が床の上ではう様子を見るのは楽しいです。
It's delightful to watch a baby crawl on the floor.
In this context, "はう" implies moving with caution, akin to the pace and care of crawling.