What does 余っ程 mean in Japanese?

very, greatly, much, considerably, to a large extent, quite

余っ程 (Yoppodo) — very · Japanese Dictionary

よっぽど

Yoppodo

Usually written in kana.

余っ程 (Yoppodo) is a Japanese adverb meaning “very, greatly, much, considerably”.

adverb, adjectival noun, na-adjectivevery; greatly; much; considerably; to a large extent; quite余 is ateji
adverbjust about to; almost; very nearly

よっぽど印象に残る事じゃないと覚えてないんだよね。
Unless it's something fairly impressive, I won't remember it.
あいつがガッツポーズするなんて、よっぽど嬉しかったんだろうな。
It must have been something really big for him to strike a triumphant pose like that.
喜色満面の笑みを浮かべているけど、彼、よっぽど嬉しいことがあったんだろうな。
You could tell by the ear-to-ear grin that came to his face that he really had something to smile about.

Sentences from Tatoeba (CC BY 2.0 FR).