Under the guise of friendship.
When you go into the kitchen and claim you are there to help, but you are really in the kitchen to steal a cookie, this is an example of a situation where you go to the kitchen under the guise of wanting to help.
Spoke to me under the guise of friendship.
Huddled on the street in the guise of beggars.
Origin of guise
- Middle English manner, fashion from Old French of Germanic origin weid- in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition