Tender, when speaking, for one for whom the earth moved? (4)
I believe the answer is:
offa
'one for whom the earth moved?' is the definition.
(king who constructed earthen barrier Offa's Dyke)
'tender when speaking' is the wordplay.
'tender' becomes 'offer' (synonyms).
'when speaking' indicates a 'sounds like' (homophone) clue.
'offer' is a homophone of 'OFFA'.
'for' acts as a link.
(Other definitions for offa that I've seen before include "King of Mercia, d. 796, with a dyke named after him" , "Old dyke builder, d. 796" , "King of Mercia who gave his name to a dyke" , "Mercia's dyke builder" , "Dividing wall builder" .)