Meaning

adjective weak in willpower, courage or vitality

adjective lacking a backbone or spinal column

adjective lacking spiny processes

originEtymology tree English spine Proto-Indo-European *lewh₁- Proto-Indo-European *lewHs-der. Proto-Germanic *leusaną Proto-Germanic *lausaz Proto-Germanic *-lausaz Proto-West Germanic *-laus Old English -lēas Middle English -les English -less English spineless From spine + -less.

Etymology from Wiktionary, CC BY-SA 3.0