I also picked up a pair of socks (3-3)
I believe the answer is:
one-two
'a pair of socks' is the definition.
I can't judge whether this defines the answer.
'i also picked up' is the wordplay.
'i' becomes 'one' (Roman numeral for one).
'also' becomes 'too' (synonyms).
'picked up' indicates a 'sounds like' (homophone) clue.
'too' sounds like 'two'.
'one'+'two'='ONE-TWO'
Can you help me to learn more?
(Other definitions for one-two that I've seen before include "Blow using fists' digits" , "Boxing or soccer manoeuvre" , "Interpassing at football - left-right at boxing" , "Soccer move" , "Pair of punches with both hands in quick succession" .)