Word to describe hidden intentions

I am looking for a term that describes a certain behavior. The example I have is in a situation where a person has malicious intent, but pretends to be innocent or even helpful. For example, if you have a “friend” that calls your wife, knowing you’re out of town. When confronted, they were just checking in on her. I am interested in a term that describes both the intent, and the type of response.

A second example could be a security guard groping a woman during a search. When confronted the response is that it was a frisk for everyone’s safety. Thank you in advance.

Solution 1:

You might be looking for -

Ulterior

: existing beyond what is obvious or admitted; intentionally hidden.

(From Lexico)

Therefore, "ulterior motive" might fit your given context -

Ulterior motive

An alternative or extrinsic reason for doing something, especially when concealed or when differing from the stated or apparent reason.

(From Wiktionary)

Solution 2:

Try this:

ruse
_{NOUN COUNTABLE}

A plan or trick for hiding your true intentions

_{Source: Macmillan Dictionary}