Historic coins, encompassing old legal tender? (10)
I believe the answer is:
solicitous
'tender?' is the definition.
(thesaurus)
'historic coins encompassing old legal' is the wordplay.
'historic coins' becomes 'sous' (sou was a historical French coin).
'encompassing' indicates putting letters inside.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'legal' becomes 'licit' (similar in meaning).
'o'+'licit'='olicit'
'sous' enclosing 'olicit' is 'SOLICITOUS'.
(Other definitions for solicitous that I've seen before include "Anxious - concerned" , "Showing concerned attention" .)