@beehelpme lol, I actually used to do that all the time. Even with words that you would never believe in a million years were actual words. I even discovered the word 'woorara' ! Thankfully I was playing an actual game with my mum so she knew I wasn't cheating! Haha.
Over time I've learn some really weird ones from other people or researching weird word lists online in my spare time (I have developed a rather strange interest in obscure words). The strangest is a 5 letter all-consonants word: 'crwth' ! (Of course, do not ask me what it means because I usually forget the definition!)
Because I'm aware that coming up with these words organically is possible, I tend to always give people the benefit of the doubt and just accept that it is certainly possible that they may have come up with the word without any cheating sites. The only time I ever decide they're cheating is when literally every word is a bingo or a 'perfect play' and they're using multiple letters on the board in weird places. They literally have to do this for a very long time and eventually I decide that either they're cheating or theyre just levels above me and if I'm not learning and just constantly questioning whether their playing is legit, I stop playing them.
This one guy even accused me of cheating and the next day accepted a game (I forgot it was him who i played) and then just did an entire game of ridiculous cheating... Even then I was giving him the benefit of the doubt until at the end I realised who it was and that he was trying to teach me a lesson in cheating when I'd never even cheated! he then blocked me... Absolutely ridiculous behaviour. I let my worse side get the better of me and logged in with a different gmail just to message him and tell him he was wrong the whole time and should take a good look at himself!
But yeah, feels good to know other people have to put up with this sort of nonsense as well.
Oh and regarding the dictionary, in professional scrabble you aren't allowed to use a dictionary, you have to play your word and if your challenger contests it and you're wrong you lose the go. I think that's right. But in non professional games of Lexulous I'm pretty sure it's allowed else why would they put a dictionary on the app I think we can live with a clear conscience!