caustic

caustic /ˈkɑːstɪk/ adjective
caustic
/ˈkɑːstɪk/
adjective
Britannica Dictionary definition of CAUSTIC
[more caustic; most caustic]
1 
: able to destroy or burn something by chemical action
2 
: very harsh and critical

— caustically

/ˈkɑːstɪkli/ adverb