– obtížný, nesnadný:

http://lila-erc.eu/data/lexicalResources/LexiconBohemorum/id/LexicalSense/3956_GF_1 an entity of type: LexicalSense

– obtížný, nesnadný: 
molestus, difficilis 
– obtížný, nesnadný: 
molestus, difficilis 

data from the linked data cloud