Thanks to Languagehat, I’ve started to read a Greek linguistics blog, Ἡλληνιστεύκοντος (link) and immediately got caught up in a thread about a rare (Modern Greek) word for the European ground squirrel (Spermophilus citellus) λαγόγηρως which occurs in Suidas. Read about it at Old Man Hare (link). There’s a Bulgarian word for the animal лалугер (variant лагудер) that looks like a loan from Greek. There are minor difficulties such as the γ mapping to the л that could be explained by dissimilation from the second γ (and the dialectal variant has the second γ becoming д). The word analyses morphologically into λαγώς ‘hare’ and γῆρας ‘old age’ hence the entry’s title. Greek λαγώς is usually traced to two PIE roots *(s)lēg (*(s)ləg, *(s)leg) ‘limp, floppy; soft’ and *ōus (*əus, *us) ‘ear’. The ο rather than an ω as in other Greek compounds with λαγώς, e.g., λαγωφόνος ‘har-killer’ , λαγώπους ‘hare-footed’ is not a problem as there are some compounds with ο, e.g., λαγοδαίτης ‘hare-devourer’. Greek γῆρας traces back to PIE *grē ‘mature, rotten’.