sp15tax_newTerm.js

$(document).ready(function(){   
  
	var scriptbase = _spPageContextInfo.webServerRelativeUrl + "_layouts/15/";
	
	$.getScript(scriptbase + "SP.Runtime.js",
        function () {
            $.getScript(scriptbase + "SP.js", function(){
            
            	$.getScript(scriptbase + "SP.Taxonomy.js", execOperation);

            });
        }
    );

});

function execOperation(){
	
    //Current Context
    var context = SP.ClientContext.get_current();
	
    //Current Taxonomy Session
    var taxSession = SP.Taxonomy.TaxonomySession.getTaxonomySession(context);
    
    //Term Stores
    var termStores = taxSession.get_termStores();
    
    //Term Store under which to create the term.
    var termStore = termStores.getByName("Taxonomy_Dmxzz8tIBzk8wNVKQpJ+xA==");
    
    //Term Set under which to create the term.
    var termSet = termStore.getTermSet("b49f64b3-4722-4336-9a5c-56c326b344d4");
    
    //Name of the term, LCID and a new GUID for the term.
    var newTerm = termSet.createTerm("India", 1033, "b49f64b3-4722-4336-9a5c-56c326b344a9");
    
    //newTerm.set_isAvailableForTagging(true);
    
    context.load(newTerm);
		
    context.executeQueryAsync(function(){
	
  	alert("Term Created: " + newTerm.get_name());
   		
     },function(sender,args){
	
	console.log(args.get_message());
	
    });

}