1) Misused participle 2) Participle, at times 3) Slang for the penis 4) Tassel on a cap 1) Tassel 
[plot device] Dangler is a literary term meaning plot-lines that are metaphorically left to `dangle` or `hang`. A dangler, or dangling plotline, is a plot device in fiction where a plotline is forgotten, phased out and eventually dropped, thus a resolution is never achieved. Although dangling plot-lines can occur in all forms of media, they...
• (n.) One who dangles about or after others, especially after women; a trifler.
A small, eye-catching sign that hangs from a product or a shelf to draw attention to an item or display. 
Dan'gler noun One who dangles about or after others, especially after women; a trifler. ' Danglers at toilets.' Burke. 
Dangler is slang for the penis.