Used to describe someone emotionally fragile; can be hurtful if used insensitively. After the breakup, he felt like such a weakling, unable to control his tears.
Pro Tip 2/3
Physical Weakness
Mostly refers to a lack of physical strength, not just general health or stamina. Even after weeks of training, he remained the team's weakling.
Pro Tip 3/3
Slightly Derogatory
Considered informal and may be taken as an insult; use cautiously in sensitive contexts. The coach's comment that he was a weakling didn't go down well with the players.