Tense, gave instruction in speech (4)
I believe the answer is:
taut
'tense' is the definition.
(I've seen this before)
'gave instruction in speech' is the wordplay.
'gave instruction' becomes 'taught' (I've seen this before).
'in speech' shows a homophone (sound like).
'taught' is a homophone of 'TAUT'.
(Other definitions for taut that I've seen before include "seaworthy" , "On the slope" , "Fully stretched" , "Tense, stretched tight" , "Pulled or drawn tight" .)