perplexing
"Dificil" is a Spanish word and it means "difficult" in English.
'Mushkil' means 'difficult' in English.
The word you're looking for is "rugged." It describes terrain that is rough, uneven, and difficult to navigate.
complex
the scientific word that means difficult swallowing is " Dysphagia " ..
When the Spanish word duro is translated into English it means hard. It also means harsh, resistant, difficult, and severe.
to solve could be analyze or identify
The English meaning of the Malayalam word samaadhanippikkuka is "to solve or resolve."
Solve -_-
Algebra actually means this, but that probably will not work as it is an Arabic word. Inference is likely the best word for it in English. Reasoning, logic, synthesis are also good.
solve?
'Intractable' means difficult to manipulate, or hard to manage.