Answer:

causer

Answer	Crossword Clue
CAUSER	The person responsible
CAUSER	To chat: Fr.
CAUSER	He who effects a result.

CAUSER	Producer.
CAUSER	One having an effect
CAUSER	Activist?
CAUSER	One producing an effect

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.