a belittling word for a woman: "little woman," used to paint someone as weak, gullible, and easily led
This is a shrunken, diminutive form of the ordinary Greek word for "woman" (γυνή). Greek often added an ending like this to make a word small, and the small-making ending could swing either way: it could sound tender and affectionate (a beloved wife, a pretty girl) or dismissive and cutting, depending entirely on the sentence around it. The word itself carries no fixed insult. Writers near the time of the New Testament use it warmly as often as sourly.
In its single appearance in the Bible, the surrounding words tip it firmly toward contempt. Paul describes women who are weighed down with sins, pulled along by all kinds of cravings, and forever learning yet never able to arrive at the truth, and he says false teachers slip into homes and "capture" them. In that frame the little word lands as a put-down: gullible, unstable, an easy mark. English Bibles have rendered it "silly," "weak," "weak-willed," "gullible," or "vulnerable."
A strong line of scholarship adds that the real sting may be aimed less at the women than at the men deceiving them. In the writing of that day, accusing a teacher of preying on impressionable women was a standard way to brand him a fraud and an unmanly hack. The women are diminished mainly to disgrace the false teachers who target them. Either way the tone is negative, but readers should notice that the harshness comes from the context Paul builds, not from the bare word.