Stealthy , stealthily ,ninja
The word for looking at someone or something secretly is "spying" or "peeking".
The word you are looking for is "conspire". It means to plan something secretly with others.
No secretly s an adverb, secret can be an adjective eg She has a secret friend
infatuated?
Covertly
Secretly is an adverb. It modifies verbs by providing information on how an action is performed.
The root word of "slowly" is "slow."
If by secretly you meant cautiously then walking stealthily or tip toeing .
talk quietly talk slowly talk fluently talk clearly talk loudly talk openly talk secretly This is not all there must be many more
secretly
Peep.
secretly talk