Crossword Genius

Old man's weapon that's need to gain access (8)

Ross

I believe the answer is:

password

I'm a little stuck... Click here to teach me more about this clue!

'need to gain access' is the definition.
I can't tell whether this defines the answer.

'old man's weapon' is the wordplay.
'old man's' becomes 'pa's' (both can mean someone's father).
'weapon' becomes 'sword' (sword is a kind of weapon).
'pas'+'sword'='PASSWORD'

'that's' is the link.

Can you help me to learn more?

(Other definitions for password that I've seen before include "Security input" , "parole" , "Shibboleth - secret phrase to gain admission" , "that'll secure one's access" , "Secret phrase needed to gain entry" .)

Want a hint initially instead of a full solution? Install my app