It may be taken in court and in boathouse (4)
I believe the answer is:
oath
'it may be taken in court' is the definition.
The definition suggests a singular noun which matches the answer.
'in boathouse' is the wordplay.
'in' says the answer is hidden in the clue.
'OATH' is hidden within 'boathouse'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for oath that I've seen before include "in court, we take it" , "darn, for example" , "exasperated comment" , "Vow, sworn word" , "Swearword, expletive" .)