galfriend
A girl who's your best friend, but not your girlfriend. She's the one who you'd fight for, but you'd never date. She's like a sister, or a crazy ex who still texts you every day and calls you a f***ing idiot.
'She's my galfriend. We've been best friends since middle school. She's also my ex and still texts me every day.'
'I wouldn't date her. She's my galfriend, and she's like my sister.'
'She's my galfriend. I know all her secrets and she still calls me a f***ing idiot.'