Show deference meeting monarch in enclosure (5)
I believe the answer is:
bower
'enclosure' is the definition.
(enclosure formed by trees)
'show deference meeting monarch' is the wordplay.
'show deference' becomes 'bow' (I've seen this in another clue).
'meeting' means one lot of letters go next to another.
'monarch' becomes 'ER' (abbreviation for Elizabeth Regina).
'bow'+'er'='BOWER'
'in' is the link.
(Other definitions for bower that I've seen before include "Shaded place under trees" , "lady's private room?" , "Shady garden place" , "Leafy shelter" , "Pleasant shady place under trees" .)