State brief time at sea not bad (9)
I believe the answer is:
minnesota
'state' is the definition.
(US state)
'brief time at sea not bad' is the wordplay.
'brief time' becomes 'min' (short for minute; 'brief' indicates a short form).
'at' says to put letters next to each other.
'bad' is an anagram indicator.
'sea'+'not'='seanot'
'seanot' is an anagram of 'nesota'.
'min'+'nesota'='MINNESOTA'
(Other definitions for minnesota that I've seen before include "source of iron ore" , "Wobegon state (Keillor)" , "American state, capital St Paul" , "Nominates the strange state" , "North Star State" .)