Careful doctor led a tribe east (10)
I believe the answer is:
deliberate
'careful' is the definition.
(synonyms)
'doctor led a tribe east' is the wordplay.
'doctor' indicates anagramming the letters.
'east' becomes 'e' (synonyms).
'led'+'a'+'tribe'='ledatribe'
'ledatribe' with letters rearranged gives 'deliberat'.
'deliberat'+'e'='DELIBERATE'
(Other definitions for deliberate that I've seen before include "Ponder" , "Consider - intentional" , "put on thinking cap" , "Cautious" , "Carefully thought out" .)