Rickrolling is an internet meme. An meme is something that spreads via the internet. If you click on a link that leads to the Rick Astley video for ‘Never gonna give you up’ you have been Rickrolled. The link is usually from someone you know and looks like it leads somewhere else.
It can be used as a noun and a verb as in
- I was Rickrolled this morning
- It is a Rickroll