Peaceful havens nomad seeks regularly (5)
I believe the answer is:
oases
'peaceful havens' is the definition.
'oases' can be an answer for 'havens' ('oasis' can be a synonym of 'haven'). I'm not sure about the 'peaceful' bit.
'nomad seeks regularly' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'nomad'+'seeks'='nomadseeks'
The alternating letters of 'nomadseeks' are 'OASES'.
Can you help me to learn more?
(Other definitions for oases that I've seen before include "Green desert spots" , "Fertile desert places" , "Where there may be dates" , "Fertile areas in deserts" , "Fertile tracts in a desert" .)