John recited with some force, that's clear (5)
I believe the answer is:
lucid
'clear' is the definition.
(similar in meaning)
'john recited with some force' is the wordplay.
I cannot really understand how this works, but
'force' could be 'cid' (abbreviation for Criminal Investigation Department) and 'cid' is located in the answer.
This may be the basis of clue (or it may be nonsense).
'that's' is the link.
(Other definitions for lucid that I've seen before include "Transparent" , "Thinking clearly" , "Clear, sane" , "Limpid" , "Easily understood; sane" .)