dark (SAD) adjective [before noun]
sad and without hope:
'Her husband's sudden death was the start of a dark chapter in her life.'
'This environmental report contains more dark predictions about the future of the Earth.'
dark (EVIL) adjective
evil or threatening:
'There's a darker side to his character.'
dark (WITHOUT LIGHT) adjective
1 with little or no light:
'It was too dark to see properly.'
'What time does it get dark in the summer?'
'Our bedroom was very dark until we put a larger window in.'
2 nearer to black than white in colour:
'dark blue/green'
'dark clouds'
'She has dark hair.'
'He was tall, dark (= with black/brown hair) and handsome.'