- deter, discourage - try to prevent; show opposition to; "We should discourage this practice among our youth"
--1 is one way to disapprove, reject
Sample sentence:Derived form: noun discouragement3 
They discourage him from writing the letter
 - discourage - deprive of courage or hope; take away hope from; cause to feel discouraged
Antonyms: encourage
Sample sentence:Derived form: noun discouragement1 
The bad news will discourage him
 - warn, discourage, admonish, monish - admonish or counsel in terms of someone's behavior; "I warned him not to go too far"; "I warn you against false assumptions"; "She warned him to be quiet"
--3 is one way to advise, counsel
Sample sentences:
Sam cannot discourage Sue
They discourage him from writing the letter