unscrupulous (Adjective) :without moral principles ; dishonest
knavish (Adjective) : dishonest; unscrupulous; without moral principles
honourable (Adjective) : following moral principles
noble (Adjective) : having fine personal qualities such as courage, honesty, etc.
trustworthy (Adjective) : reliable; that you can rely on to be good, honest, sincere, etc.

Correct Option: D

unscrupulous (Adjective) :without moral principles ; dishonest
knavish (Adjective) : dishonest; unscrupulous; without moral principles
honourable (Adjective) : following moral principles
noble (Adjective) : having fine personal qualities such as courage, honesty, etc.
trustworthy (Adjective) : reliable; that you can rely on to be good, honest, sincere, etc.

original (Adjective) : existing at the beginning of a particular period
genuine (Adjective) : real ; not artificial ; authentic
generous (Adjective) : giving or willing to give freely
healthy (Adjective) : having good health
natural (Adjective) : existing in nature ; not made by humans

Correct Option: D

original (Adjective) : existing at the beginning of a particular period
genuine (Adjective) : real ; not artificial ; authentic
generous (Adjective) : giving or willing to give freely
healthy (Adjective) : having good health
natural (Adjective) : existing in nature ; not made by humans

gloomy (Adjective) : nearly dark or badly lit ; feeling sad ; depressing
sombre (Adjective) : dark in colour ; dull ; sad and serious
quiet (Adjective) : making very little noise
serious (Adjective) : bad or dangerous
sleepy (Adjective) : needing sleep

Correct Option: A

gloomy (Adjective) : nearly dark or badly lit ; feeling sad ; depressing
sombre (Adjective) : dark in colour ; dull ; sad and serious
quiet (Adjective) : making very little noise
serious (Adjective) : bad or dangerous
sleepy (Adjective) : needing sleep

backslide (Verb) : drop to a lower level in one’s morals or behaviour
regress (Verb) : to return to an earlier or less advanced form or way of behaving
deteriorate (Verb) : to become worse (bad to worse)
degenerate (Verb) : deteriorate
lapse (Verb) : to be no longer valid because the period of time that it lasts has come to an end

Correct Option: C

backslide (Verb) : drop to a lower level in one’s morals or behaviour
regress (Verb) : to return to an earlier or less advanced form or way of behaving
deteriorate (Verb) : to become worse (bad to worse)
degenerate (Verb) : deteriorate
lapse (Verb) : to be no longer valid because the period of time that it lasts has come to an end

poisonous (Adjective) : toxic, containing poison
toxic (Adjective) : containing poison ; poisonous
bitter (Adjective) : not sweet foul-smelling (Adjective) : smell bad
remedial (Adjective) : aimed at solving a problem (medical)

Correct Option: D

poisonous (Adjective) : toxic, containing poison
toxic (Adjective) : containing poison ; poisonous
bitter (Adjective) : not sweet foul-smelling (Adjective) : smell bad
remedial (Adjective) : aimed at solving a problem (medical)