Could mean lucky, could be doubtful.
In written prose: So far, his knack for fatherhood seems iffy at best.
Planning commissioner: That adaptive resuse plan looks iffy to me.
Consultant: I have no idea what you mean.
There was a young lamp shade from Liffey,
Whose golden cheek blushes were iffy,
She met a half-sconce and
They lived for the nonce
On dust motes and Tolstoy and Jiffy.