forever
Synonym discussion
Sense: adverb/1
All four words describe something that lasts or continues, but they differ in register and scope. 'Forever' (the most common, A2-level word) is emotional and personal — people promise to love someone forever or hope good memories last forever. 'Permanently' is more factual and neutral; you might say the museum is permanently closed or the damage is permanent. 'Eternally' carries poetic or spiritual weight, often referring to the divine or to unchanging truths ('eternally grateful'). 'For good' is informal and suggests a decisive, final end: 'She left for good' means she is never coming back. Use 'forever' for heartfelt personal statements, 'permanently' for official or formal contexts, 'eternally' for dramatic or religious tones, and 'for good' for casual statements about final decisions.
Common collocations
Etymology
From Middle English 'for ever,' a phrase meaning 'for all time.' The two-word form 'for ever' was standard through the 16th century, and gradually the single-word 'forever' became common in the 17th and 18th centuries. The adverbial phrase was formed from 'for' (meaning 'throughout' or 'during') + 'ever' (meaning 'always' or 'at all times'). The noun use (e.g., 'it took forever') emerged in informal 19th-century English, and the adjective use (e.g., 'forever home') developed in the late 20th century.