Duck into street, hot for underhand action (7)
I believe the answer is:
stealth
'underhand action' is the definition.
'stealth' can be an answer for 'action' (I have seen 'Surreptitious action ' mean 'stealth' so perhaps 'action' could also mean 'stealth'). I am not certain of the 'underhand' bit.
'duck into street hot' is the wordplay.
'duck' becomes 'teal' (teal is a type of duck).
'into' means one lot of letters goes inside another.
'street' becomes 'st' (abbreviation).
'hot' becomes 'h' (abbreviation, eg on taps).
'teal' inserted into 'st' is 'stealt'.
'stealt'+'h'='STEALTH'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for stealth that I've seen before include "Avoiding detection by moving carefully" , "By which taxes go up" , "Avoidance of detection by moving carefully" , "Skill in furtive activity" , "Unseen machination" .)