More irritable sailor up on deck (7)
I believe the answer is:
rattier
'more irritable' is the definition.
Both the definition and answer are comparative adjectives. Maybe they are linked in a way I don't understand?
'sailor up on deck' is the wordplay.
'sailor' becomes 'tar' (tar can mean a sailor).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'on' means one lot of letters go next to another.
'deck' becomes 'tier' (I've seen this in another clue).
'tar' in reverse letter order is 'rat'.
'rat'+'tier'='RATTIER'
Can you help me to learn more?
(Other definitions for rattier that I've seen before include "more annoyed" , "Not so placid" , "more likely to snap?" , "More bad tempered (colloquial)" , "more irritable mood" .)