Write about Ives being thoughtful (7)
I believe the answer is:
pensive
'thoughtful' is the definition.
(similar in meaning)
'write about ives' is the wordplay.
'write' becomes 'pen' (synonyms).
'about' is an anagram indicator.
'ives' anagrammed gives 'sive'.
'pen'+'sive'='PENSIVE'
'being' is the link.
(Other definitions for pensive that I've seen before include "musing" , "Meditative" , "in a brown study?" , "Engaged in deep thought" , "Preoccupied" .)