adjective
loose, relaxed
B1
'locker' is an adjective meaning 'loose' (physically) or 'relaxed' (manner, atmosphere). Top translations: loose; relaxed. It is gradable: comparative 'lockerer', superlative 'am lockersten'. Antonyms: streng, angespannt, fest. Not a participle or reflexive; use normal German adjective endings for gender, number, and case.
Examples
Die Schraube ist locker und muss festgezogen werden.
The screw is loose and needs to be tightened.
Der Monteur zog die lockere Schraube fest, weil sonst die Maschine gefährlich vibrieren würde.
The mechanic tightened the loose screw because otherwise the machine would vibrate dangerously.
Er ist sehr locker in sozialen Situationen und spricht offen mit Fremden.
He is very relaxed in social situations and speaks openly with strangers.
Details
Mnemonics
Imagine a loose shoelace that is 'locker' (not tight).
Sounds a bit like 'locker' in English — something loose.