Learn English – How to say “full of obstacles” with one word

single-word-requests

…paving the [full of obstacles] way to fluency.

Is there a one-word adjective I can use to replace that outrageous 3-word one?

I swear I've heard of it somewhere, but I've been searching for it for almost an hour now, and have come no closer to success than when I began.

Best Answer

Given that the phrase the desired word is going to be inserted into is a metaphor about paving a road, perhaps "rocky" will serve. This sense of the word is defined by oxforddictionaries.com as

Difficult and full of problems