It's a fruit that used to be called waninashi.
Katakana spelling is common for this loanword; usually written in kana.
Ateji kanji spelling; rarely used in modern writing.
From English 'alligator pear', an old name for avocado. The kanji 鰐梨 is ateji, combining 鰐 (alligator) and 梨 (pear).