conscienceless
adjective
- having no, or habitually disregarding, conscience/scruples/morality
Wiktionary
adj
Etymology: Etymology tree English conscience 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 conscienceless From conscience + -less.
- Lacking a conscience; unscrupulous or ruthless.
“It was watching her with cold animal curiosity, something demonish and conscienceless.”