Defensive position ending in defeat, occupying beach (5)
I believe the answer is:
stand
'defensive position' is the definition.
'stand' can be an answer for 'position' (stand is a kind of position). I'm not sure about the 'defensive' bit.
'ending in defeat occupying beach' is the wordplay.
'ending in' suggests the final letters.
'occupying' means one lot of letters goes inside another (inserted letters occupy or enter the word).
'beach' becomes 'sand'.
The last letter of 'defeat' is 't'.
't' placed into 'sand' is 'STAND'.
Can you help me to learn more?
(Other definitions for stand that I've seen before include "remain in force" , "Set up" , "Sit here at a sports event" , "Base < put up with" , "Remain stationary" .)