size up

present singular third person sizes up · participle present sizing up · participle past sized up · past sized up

1. idiomatictransitiveTo evaluate; to estimate or anticipate the magnitude, difficulty, or strength of something.

   The Century We had to size up our fellow legislators.

   3 more examples

   It's a good idea for boxers to size up their opponents before their matches.

   Before we can begin to size up the problem, we'll need more information.

   She approaches like she’s sizing them up. Five boys. Unarmed. A pile of swords over there. Ed Sheeran is there, but that’s not even the surprise.

   2017 July 16, Brandon Nowalk, “Chickens and dragons come home to roost on Game Of Thrones (newbies)”, in The Onion AV Club, archived from the original on 03 Aug 2017

2. intransitiveTo wear a larger size of clothing.

   This shirt runs tight, so you should size up.