Obstacle to getting off home? One moans terribly (8)
I believe the answer is:
insomnia
'obstacle to getting off' is the definition.
(get off can mean to get to sleep)
'home? one moans terribly' is the wordplay.
'home?' becomes 'in' ('he's home' can mean 'he's in').
'one' becomes 'I' (Roman numeral).
'terribly' indicates an anagram.
'i'+'moans'='imoans'
'imoans' with letters rearranged gives 'somnia'.
'in'+'somnia'='INSOMNIA'
(Other definitions for insomnia that I've seen before include "problem at night" , "Sleep disorder" , "Inability to drop off" , "State of chronic sleeplessness" , "Wakefulness" .)