Simpers, out to influence (7)
I believe the answer is:
impress
'influence' is the definition.
(thesaurus)
'simpers out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'simpers' anagrammed gives 'IMPRESS'.
'to' is the link.
(Other definitions for impress that I've seen before include "Move, affect" , "Produce a strong, lasting impression on" , "Stamp, emboss" , "Inspire respect, stamp" , "Make mark on, cause to admire" .)