Old English fællan (Mercian), fyllan (West Saxon) "make fall, cause to fall," also "strike down, demolish, kill," from Proto-Germanic *falljanan "strike down, cause to fall" (source also of Old Frisian falla, Old Saxon fellian, Dutch fellen, Old High German fellen, German fällen, Old Norse fella, Danish fælde), causative of *fallanan (source of Old English feallan; see fall (v.)), showing i-mutation. Related: Felled; feller; felling.
an attempt at a phonological spelling of a casual pronunciation of fellow (n.), attested by 1864 (as fellah). Feller, along the same lines, is recorded by 1825. Earlier, Pope rhymes fellow with prunella ("Essay on Man," epistle IV).
<a href="https://www.etymonline.com/word/feller">Etymology of feller by etymonline</a>
Harper, D. (n.d.). Etymology of feller. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/feller