Swearing bothered a host (5)
I believe the answer is:
oaths
'swearing' is the definition.
(I've seen this in another clue)
'bothered a host' is the wordplay.
'bothered' is an anagram indicator.
'a'+'host'='ahost'
'ahost' is an anagram of 'OATHS'.
(Other definitions for oaths that I've seen before include "truths may be established by them" , "Solemn vows" , "professions of loyalty" , "Solemn sworn promises" , "Imprecations" .)