German ties underwear (1-7)

'underwear' is the definition.
Although both the answer and definition are nouns, they are not in the same form of the noun.

'german ties' is the wordplay.
I cannot quite understand how this works, but
'german' could be 'g' (abbreviation) and 'g' is found in the answer.
'ties' could be 'strings' ('string' can be a synonym of 'tie') and 'strings' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?