1
instransigent
stubborn
2
levity
humor and frivolity
3
invective
insulting
4
misanthropic
hating or having contempt for humankind
5
pejorative
disparaging or belitting
6
sentient
conscious and aware
7
tirade
rant
8
alacrity
prompt and cheerful
9
crestfallen
deject/sad/disappointed
10
germane
revevant and fitting to situation
11
paramount
superior
12
inscrutable
unfathomable
13
substantiate
strengthen with new evidence
14
plausible
possibly true
15
assiduous
showing great care