- injurious to health: deleterious gases.
- harmful; injurious: deleterious influences.
Origin of deleterious
1635–45; < Greek dēlētḗrios destructive, adj. derivative of dēlētḗr destroyer, equivalent to dēlē- variant stem of dēleîsthai to hurt, injure + -tēr agent suffix + -ios adj. suffix; see -ious
SynonymsSee more synonyms for deleterious on Thesaurus.com
2. pernicious, hurtful, destructive; noxious.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for undeleterious
It contained inhabitants of as undeleterious and self-satisfied a class of peasantry as ever clustered around a Maypole.
- harmful; injurious; hurtful
C17: from New Latin dēlētērius, from Greek dēlētērios injurious, destructive, from dēleisthai to hurt
Word Origin and History for undeleterious
1640s, from Medieval Latin deleterius, from Greek deleterios "noxious," from deleter "destroyer," from deleisthai "to hurt, injure." Related: Deleteriously; deleteriousness.
Online Etymology Dictionary, © 2010 Douglas Harper
- Having a harmful effect; injurious.