Imply is a synonym of Assume. Assume is a synonym of Undertake. Undertake is a synonym of Contract. Charter is a type of Contract. 
Charge is a type of Request. Charge is related to Military. 
Imply <--Synonym--> Assume <--Synonym--> Undertake <--Synonym--> Contract <--IsA-- Charter 
Request <--IsA-- Charge <--RelatedTo--> Military 