Clandestine
Secret, usually immoral or dishonest
Efficacy
Effective
Evoke
To cause or bring about something e.g. feelings
Vantage
a place or position affording a good view of something
Revitalise
To bring to life again or to make fresh
Sluice
an act of rinsing or showering with water
Comprehension
Understanding
despicable
deserving hatred and contempt
Exhibitionism
when someone behaves in ways intended to attract attention, usually sexual