Following are all the undercover like words, in the list below.
CLOAK-AND-DAGGER
100% like undercover
HOLE-AND-CORNER
100% like undercover
CLANDESTINE
100% like undercover
COVERT
100% like undercover
SURREPTITIOUS
100% like undercover
ON THE QUIET
100% like undercover
SECRET
99.99% like undercover
HUSH-HUSH
99.99% like undercover
HUGGER-MUGGER
99.99% like undercover
UNDERGROUND
99.54% like undercover
SECRETIVE
66.72% like undercover
SECRECY
66.72% like undercover
CONFIDENTIAL
66.71% like undercover
CONFIDENTIALITY
66.71% like undercover
DISGUISED
66.71% like undercover
HEDGING
66.71% like undercover
HIDDEN
66.69% like undercover
ILLEGAL
66.69% like undercover
INSIDE
66.65% like undercover
INCOGNITO
66.64% like undercover
IRREGULAR
66.62% like undercover
INVISIBLE
66.61% like undercover
ANONYMOUS
66.6% like undercover
NARC
66.59% like undercover
AGENT
66.59% like undercover
CIVILIAN
66.57% like undercover
CLASSIFIED
66.56% like undercover
CIVIL
66.55% like undercover
PLAIN-CLOTHES
66.52% like undercover
OFFICER
66.51% like undercover
BACKDOOR
66.51% like undercover
UNMARKED
66.51% like undercover
COVERAGE
66.45% like undercover
JOURNALIST
66.43% like undercover
WAY
66.42% like undercover
SEEPAGE
66.4% like undercover
COVER
66.39% like undercover
LID
66.39% like undercover
INFILTRATION
66.35% like undercover
BLANKET
66.28% like undercover
CAP
66.23% like undercover
LOW
66.18% like undercover
SUBMARINE
66.18% like undercover
COUVERTURE
65.66% like undercover
NARCS
33.45% like undercover
UNDERCOVERS
33.45% like undercover
SPIES
33.45% like undercover
SHADY
33.45% like undercover
INFILTRATOR
33.45% like undercover
OPERATIVES
33.45% like undercover
SURVEILLANCE
33.45% like undercover
INFILTRATE
33.45% like undercover
HIDEOUT
33.45% like undercover
COUNTERSPY
33.45% like undercover
RENEGADE
33.45% like undercover
GUERILLA
33.45% like undercover
DETECTIVE
33.45% like undercover
GUNRUNNING
33.44% like undercover
PLAINCLOTHES
33.44% like undercover
SMUGGLING
33.44% like undercover
GUNRUNNERS
33.44% like undercover
GUERRILLA
33.44% like undercover
SPYING
33.44% like undercover
OPERATIVE
33.44% like undercover
OUTDOOR
33.44% like undercover
COUNTERSURVEILLANCE
33.44% like undercover
BODYGUARD
33.44% like undercover
STAKEOUTS
33.44% like undercover
STAKEOUT
33.44% like undercover
POLICEWORK
33.44% like undercover
POLICE
33.44% like undercover
COMMANDO
33.44% like undercover
COUNTERINTELLIGENCE
33.44% like undercover
SMUGGLER
33.44% like undercover
PATROL
33.44% like undercover
COUNTERESPIONAGE
33.44% like undercover
PARAMILITARY
33.44% like undercover
ROGUE
33.44% like undercover
SURVEILLANCES
33.44% like undercover
MOONLIGHTING
33.44% like undercover
INVESTIGATIVE
33.44% like undercover
INVESTIGATOR
33.44% like undercover
PRIVATE
33.44% like undercover
SAFEHOUSE
33.44% like undercover
DETECTIVES
33.44% like undercover
SUPERSECRET
33.44% like undercover
SNITCH
33.44% like undercover
GANGSTER
33.44% like undercover
SLEUTH
33.44% like undercover
HIDEAWAY
33.44% like undercover
CLANDESTINELY
33.44% like undercover
WAREHOUSE
33.44% like undercover
INTERROGATION
33.44% like undercover
GUNRUNNER
33.44% like undercover
SNOOPING
33.44% like undercover
GESTAPO
33.44% like undercover
COPS
33.44% like undercover
ASSASSIN
33.44% like undercover
ULTRASECRET
33.44% like undercover
MOSSAD
33.44% like undercover