Have you ever been told ‘trickish’ is not an English word? Or that it’s from Nigerian English?
Seems most of us have, but that’s not true.
‘Trickish’ is no longer popular because it’s an old-fashioned word (adjective) used to describe a behaviour or skill that is intended to deceive or trick.
The word is still used in Scrabble in the UK, US, Canada, etc. and entered in popular dictionaries (e.g. https://en.oxforddictionaries.com/definition/trickish).
You can avoid using it because of its acceptability status and use ‘tricky’ instead, but don’t say it’s not an English word.