I don’t like students depending on dictionaries in class (in fact, I don’t like them using dictionaries at all), for several reasons, another of which I might write about in a future post. Last night the students were practicing changing nouns into adjectives and vice versa (for the sake of completeness, I also added the appropriate verbs and adverbs). Most nouns change to adjectives and vice versa by the addition or subtraction of a suffix. However, there is a group of words which are clearly related but include other changes (long > length, strong > strength etc), sometimes enough to classify them as two different words (poor > poverty).
One word was heat, for which most students had no trouble finding hot. (Though one student wrote tropical.) Another student then said ‘What about heatable and heatful?’. I said ‘What?!’. He pointed at the dictionary app on his phone. I said approximately ‘Well, I understand I those words but I’ve never seen or heard them in my life. Forget them. If you’ve ever got a choice between hot, heatable and heatful, keep it short and simple, and choose hot.’
One of the reasons I don’t like students depending on dictionaries in class, then, is that they sometimes offer too many choices, without indicating how common or rare those choices are. The full online version of the app the student was using lists as ‘related words’: heatable, heatful, heatless, heatlike, reheat, reheatable, self-heating, underheat, unheatable, but not hot (which does, however, appear in some of the definitions – which doesn’t really help heat is defined as ‘the condition or quality of being hot’ and hot is defined as ‘having or giving off heat’).
Are heatable and heatful actual words? (I wouldn’t preclude a word from being ‘an actual word’ simply because I’ve never seen or heard it. My personal vocabulary is in the tens of thousands, while English includes at least hundreds of thousands of words, which means I might know about one in ten – which is a slightly depressing thought, now I think about it.) Clicking on those words in that online dictionary simply returns me to the same page. Pages for Mac red-underlines heatful, heatlike and reheatable, though I’ve got no problems with reheatable. WordPress’s text editor accepts only reheat and self-heating. Searching Google Ngrams for ‘heatable *’ returns brick, room, sample and rooms, but ‘heatful *’ returns no results, as do ‘* is/are/was/were reheatable/heatful’. A Google search for heatable returns 1,130,000 results. Another online dictionary gives the expected definition ‘capable of becoming hot’ and the example ‘the heatable tip of a soldering iron’. Other heatable items are slippers, glass and soft toys.
A Google search for heatful returns 16,800 results. A major dictionary defines it as ‘full of or producing heat especially : capable of releasing abundant heat in combustion’. I can’t think of a single circumstance in which anyone would choose heatful over hot or combustible. (I can’t imagine the Wonder Girls singing ‘I’m so heatful’, because the Korean songwriter just happened to find that word in a dictionary app.)
So, I’m prepared to accept heatable as a word, but would probably never use it. I’m unconvinced that heatful is a word, even though I recognise its meaning even out of any context. Certainly, though, the answer to the exercise in the textbook is hot. Don’t make any more choices than you have to.