If girl have coarse, thick, black hair growth on any part of her body like armpit, pelvic(vagina/vulva), arms,legs,abdomen,chin etc; then are they considered as haram ? Are light, thin and less hair growth is halal? Explain with sharah reference. If unmarried girl have coarse thick hairs on her any part of body specially hidden(pelvic/vulva) then have she committed zinna? How true it is that married girls can have such hair & its a sin for unmarried girl? I am asking this question on behalf of this point that people consider those girls are bad and not pious and have performed any unethical deed(like haram or touching of non-mehram)that she possess such hair, is it true in islam too?
"people consider those girls are bad and not pious and have performed any unethical deed(like haram or touching of non-mehram)that she possess such hair, is it true in islam"
No. I am sorry brother, but such beliefs suggest major jahiliyyah (ignorance), no offense to you if your family members or friends have such beliefs.. but they need to change them so you should guide them. A woman's level of piety is not based on whether she has thick or thin hair, but based on her actions; you cannot assume a woman is unethical [to the point of Zina] based on her hair type. SubhanAllah.
Prophet Muhammad (ﷺ) said (read here) that removing armpit hair and pubic hair is of the fitrah i.e., natural things to be done. He didn't put conditions on hair type. So it doesn't matter if this hair is thick/course/black (easily seen) or thin/subtle/light (less noticeable). Women of both hair types have to remove it. In that sense, failure to do so [every 40 days minimally] is an unnatural/unethical action. But even then, it is not to the level of Zina.
[Hair everywhere else is up to her discretion, minus eyebrows which are haram to shave/pluck].
The Prophet (ﷺ) didn't put a condition on marital status either. Both married and unmarried women have to remove it. Every 40 days is the minimum time limit, but married women should remove it even sooner, since they have a reason to do so i.e., they are intimate with their husbands and such hair is visually displeasing to them.