A strong female character is meant to be a character which combines natural femininity with an ability to succeed in the face of adversity. Take Ellen Ripley from Alien as an example. She looks good, she's naturally feminine, she doesn't hide the fact that she's a woman but she doesn't obsess about it either. She's not strong "in spite of" being a woman, she's strong because she's simply a woman who does what needs to be done to survive.
What SJW's THINK "strong female character" means is a rude, aggressive creature which is barely identifiable as female, which needlessly and pointlessly rebel against what they consider "traditional femininity" by being ugly, crass, stupid and loud. At its core, it's just a dull soapbox for their idiotic, cancerous ideology, shallow as a salt lake and utterly disgusting.