Can staff have character that's heartless? (3,3)
I believe the answer is:
tin man
'character that's heartless?' is the definition.
(character with no heart in The Wizard of Oz)
'can staff' is the wordplay.
'can' becomes 'tin' (synonyms).
'staff' becomes 'man' (as in staffing or manning a particular place).
'tin'+'man'='TIN MAN'
'have' is the link.
(Other definitions for tin man that I've seen before include "He seeks for a heart in Oz" , "6 [FRIEND OF DOROTHY]" , "one in 5d's company" .)