A conniption fit is a spontaneous outburst of anger or frustration, usually precipitated by an act of stupidity or neglect. Wild animation, gesticulations, and flailing of limbs often accompanies said outburst, adding visual flavor to the experience.
"If your mothergets home before you clean this up, she'll have a conniption fit!"
Someone who secretly makes plans behind her husband's back to leave him while pretending to attend counseling to reconcile the marriage.
i.e. A conniving cunt is someone who opens her own bank account to transfer funds; says she is going to meet friends she has no plans on meeting; or, leaves a note for her husband asking for a divorce after 17 years. She hides things in YOUR home to help hide the affair for her best girlfriend. She is someone who has no respect for her own marriage or of her friends marriage. Someone you ultimately cannot trust.