Unfavorable, Hostile; an __ Reaction
Puzzle 15 of Group Activities Easy Pack
Question is: Unfavorable, Hostile; an __ Reaction
and the answer is: ADVERSE
Word Meaning:
ADVERSE — Unfavorable; antagonistic in purpose or effect; hostile; actively opposing one's interests or wishes; contrary to one's welfare; acting against; working in an opposing direction.
Definitions from Wiktionary.