Let Possibility Be Your English Language Grammar Guide

The connection between physical possibility and grammar came up recently while playing the NYT Spelling Bee game. The object of the game is to create words using seven letters. While playing the game, we discovered a “category” of words that always caught us off guard. That category contains verbs where you can’t use the prefix “un” but “un” as a prefix makes sense for the adjective derived from the verb. For example, in the puzzle, we would get “uncooked” and then pause for a second wondering why “uncook” wasn’t acceptable. 

In English (and I’m sure there are exceptions!), we don’t use “un” before the following verbs when there is another word that expresses the idea, and when it doesn’t make sense in terms of being physically possible to do the reverse of the verb. Think of the classic physics problem of the cup of coffee smashing to the floor: reversing the process is not possible (or better to say probable).

• bake, unbake (don’t bake), unbaked
• cook, uncook (don’t cook, raw), uncooked
• discover, undiscover, undiscovered
• remember, unremember (forget), unremembered
• break, unbreak, unbroken
• boil, unboil, unboiled
• play, unplay, unplayed
• live, unlive (die), unlived
• sit, unsit (stand)
• Others: break, expect, melt, own seek, smile, sleep.

You can’t uncook, unboil, or unmelt something. These actions would not be physically possible (or again, not very probable). But you could have an uncooked meal, an unboiled egg, or unmelted chocolate. using the adjectives derived from the verbs.

However, you can use “un” as a prefix with verbs when the reverse action makes sense physically.

• freeze, unfreeze, unfrozen
• thaw, unthaw (use thaw), unthawed (use thawed)
• peel, unpeel, unpeeled
• wrap, unwrap, unwrapped
• coil, uncoil, uncoiled
• do, undo, undone
• wrap, unwrap, unwrapped
• screw, unscrew, unscrewed
• fasten, unfasten, unfastened
• mask, unmask, unmasked
• bend, unbend, unbent
• cover, uncover, uncovered
• dress, undress, undressed
• Others: lock, leash, load, plug, tie, wind

Also, there are recent additions from social media:

• follow, unfollow, unfollowed
• like, unlike, unliked
• friend, unfriend, unfriended
• watch, unwatch, unwatched

References:

• adjectives - How productive is the verb prefix "un-"? - English Language & Usage Stack Exchange 
• meaning - Prefixes for the opposite of "perishable": unperishable, non-perishable, imperishable - English Language & Usage Stack Exchange 
• The Un-Believable Un-Verb : Word Routes : Thinkmap Visual Thesaurus
• Static and Dynamic Verbs