Hi Team,

I have to import Term set csv into SharePoint online environment using CSOM Code? Can somebody give me the direc

I don't think there is CSOM to invoke a simple import.  But you can build Termsets using CSOM code.  It will just take a bit more work and more code since you'll have to write code to read the CSV and then create the Termstore, term group, termsets, and terms.  Take a look at this sample:

https://msdn.microsoft.com/EN-US/library/office/dn904534.aspx#sectionSection1