Answer:

sabotage

Answer	Crossword Clue
SABOTAGE	Undermine
SABOTAGE	Enemy agent's strategy
SABOTAGE	Spy's doing

SABOTAGE	Monkey-wrenching
SABOTAGE	Luddite's offense
SABOTAGE	1936 Hitchcock thriller
SABOTAGE	Mole activity, possibly
SABOTAGE	His 1936 film
SABOTAGE	Deliberate destruction
SABOTAGE	"Hogan's Heroes" activity
SABOTAGE	Underground activity in France.

SABOTAGE	Malicious undermining of a cause.
SABOTAGE	Strategic monkey wrench in the works.
SABOTAGE	Resistance specialty.
SABOTAGE	Destroy, figuratively.
SABOTAGE	Activity of subversive groups.
SABOTAGE	Subversive act
SABOTAGE	Enemy agent's act
SABOTAGE	Underground activity

SABOTAGE	Deliberate subversion
SABOTAGE	Planned destruction
SABOTAGE	Deliberately gum up the works
SABOTAGE	"Mission: Impossible" assignment, maybe
SABOTAGE	Throw a monkey wrench into
SABOTAGE	Obstruct deliberately
SABOTAGE	Hitchcock classic, 1936
SABOTAGE	Hitchcock thriller

SABOTAGE	Hitchcock classic of 1936