Because it is imperative that the sonar devices don't crash on the rugged sea floor terrain, millions had to be spent before their launch on detailed mapping of the seabed.
Times, Sunday Times (2015)
That's 63 miles each way, across ruggedterrain.
Times, Sunday Times (2016)
I drove it on a treacherous course in the ruggedterrain of Virginia.
The Sun (2006)
Seerough terrain
Definition of 'rugged'
rugged
(rʌgɪd)Explore 'rugged' in the dictionary
adjective [usually ADJECTIVE noun]
A rugged area of land is uneven and covered with rocks, with few trees or plants.