Like lourd, relou is used to talk about someone or something that is irritating or oppressive, but the verlan version, probably because it is less formal and more slangy, carries a little bit of extra oomph.
Relou is probably most frequently used when talking about a person whose presence or behaviour is or has become oppressive:
Au début, Pierre semblait cool, mais il est devenu trop relou – At first, Pierre seemed cool, but he got really annoying.
Especially when applied to a man, relou usually refers to the sort of guy who makes bad jokes, lacks tact, and doesn't know when their presence is unwanted… think Michael Scott from the Office (or David Brent in the UK version), seen without any sympathy.
Arrête de la draguer tout le temps, t'es relou! – Stop hitting on her all the time, you're a pain in the ass!
It can also be used to describe a disagreeable situation, much like ‘that sucks' in English.
Comment ça se passe, le travail à Paris ? – Je ne fais que métro, boulot, dodo, c'est relou. – How's the job in Paris going? – I do nothing but commute, work, and sleep, it sucks.
While we're on the theme of being pissed off, vénère is a handy one to have. It's verlan for énervé, meaning ‘irritated', ‘angry', or even ‘pissed off' – the first and last ‘é' are combined (énervé -> vé-éner -> vénère).
As in, Je suis trop vénère, ta soeur m'a piqué mon mec ! – I'm really angry, your sister stole my man!
As it means ‘angry' or ‘irritated', the word vénère is often used by protesters, like the students at the University of Paris Nanterre protesting against the Macron government's 2018 higher education reform, who called themselves Nanterre Vénère.
For people above a certain age, this might be what you say when you get up from a low chair, but in verlan its meaning is very different.
The word being inverted is fou (crazy).
As well as being used on its own to describe something crazy, mad or generally bizarre, ouf is often seen as part of the phrase un truc de ouf (a crazy thing).
If you saw a film that really blew your mind you might say, c'était un truc de ouf! It was so good!.
Or, to describe a negative experience you might say Je suis bloqué dans un embouteillage, dépuis 8h. C'est un truc de ouf! I've been stuck in a traffic jam since 8 am. It's crazy.
And just because you're down with the kids, there's no reason to stop being polite. Cimer is the inverted form of merci (thank you).
So if you do someone a favour, you might hear them respond with T’es trop sympa, cimer! – you're too nice, thanks.