Adjective for "Cover up or conceal nefarious activity"

What is an adjective describing behavior used to cover up or conceal nefarious activity, as in a "smoke screen"? For example:

His _____ nightly coughing fits were meant to drown out the rattle of the window opening as the girl crept in.

"behavior used to cover up or conceal nefarious activity"

"cunning" implies the use of artful deceit and seems like a good fit.

"His cunning coughing fits were meant to drown out the rattle of the window opening as the girl..."

• "cunning" - adj. crafty and shrewd, esp in deception; sly: cunning as a fox. TFD. Someone who is cunning has the ability to achieve things in a clever way, often by deceiving other people. Collins

e.g.

• "The clever folk in management came up with a cunning plan."
• "Their cunning plan was to turn the by-election into a referendum on the EU."

You are looking for one of two words, depending on the final lexical environment you go with.

As it is now, the best fit, I think, is feigned. 'His feigned nightly coughing fits...'

You might also use ostensible, but I usually encounter that one as an adverb, so you might reword slightly to fit convention.

Cheers!