Gave instruction in speech for tense (4)
I believe the answer is:
taut
'tense' is the definition.
(similar in meaning)
'gave instruction in speech' is the wordplay.
'gave instruction' becomes 'taught' (I've seen this before).
'in speech' indicates a 'sounds like' (homophone) clue.
'taught' sounds like 'TAUT'.
'for' is the link.
(Other definitions for taut that I've seen before include "seaworthy" , "Stretched, pulled tight" , "Pulled or drawn tight" , "Fully stretched" , "Tense, stretched tight" .)