incredulous
atheist
atheistic
creedless
faithless
heathen
heretical
infidel
infidelic
irreligious
minimifidian
nonbelieving
nullifidian
pagan
questioning
quizzical
repudiative
skeptical
unbelieving
unchristian
unconfident
unconverted
unconvinced
without faith
achieving
believing
conceiving
deceiving
grieving
heaving
interleaving
interweaving
leaving
misconceiving
perceiving
receiving
relieving
retrieving
self-deceiving
thieving
weaving