gain weight
consider
take to heart
self-serious
shoot someone straight
nonseriousness
earnest
sober up
sober
make a move
seriousness
overseriousness
trifle
attend to
play
earnestness
dally
chalance
serious-mindedness
sincerity
take someone at their word
deal
step up to the plate
carry the can
raise a stink
make a stink
reflect
raise hell
seriositude
in earnest
seriously
earnestly
face up
deal with
choose
Pooterism
straightness
good faith
no joke
keep it a buck
stand up on one's hind legs
pragmatise
deedy
if I'm honest
seriosity
straight
see to
be all about
step up
unfacetious